Landscape Horticulture — Shrubs

 

My azalea leaves are turning yellow - what is the problem?

Azaleas are acid lovers. Certain minerals, including iron, are more available at lower pH values. Yellow leaves on azaleas can indicate an iron deficiency because (1) not enough iron is present in the soil for the azaleas to utilize, or, more commonly, (2) the pH is too high to release the iron that is present. Azalea fertilizer is usually a sufficient acidifier to keep the soil within the proper pH range for maximum nutrient availability. Supplemental applications of iron in the form of iron sulfate or iron chelate will supply iron when the azalea fertilizer is inadequate.

It is nearly impossible to permanently adjust a naturally alkaline soil. Therefore, azaleas and other acid-loving plants should not be selected for that site.

Also remember that mites, poor drainage, low nitrogen, and/or too much sun can also turn leaves yellow.

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How deep should I plant my trees and shrubs?

Never transplant ornamental trees and shrubs any deeper than they were already planted. After digging the planting hole only as deep as the root ball, backfill around the root ball using existing soil so that the plant will sit in the hole at the same level it was growing in the container. Research indicates that the addition of organic amendments is not needed.

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Every fall the older leaves on my gardenia and hibiscus shrubs turn yellow and drop, what could cause this?

When healthy gardenias and hibiscus are exposed to cool evening temperatures and warm days, it is not uncommon for some older leaves to turn bright yellow and drop. There is no treatment or prevention for this since this is normal. If yellow leaves and leaf drop occur at other times of the year, it is a sign of stress resulting from water stress, improper fertilization, root disorders, nematodes, or misuse of chemicals.

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Why didn't my poinsettia bloom by Christmas?

This could have resulted from a couple of problems. First, poinsettia should not be pruned after September 10th. Flower buds are set sometime between September 10th and shortly after October 10th. Pruning anything within this period could remove those initiated flower buds.

Secondly, flower initiation in poinsettias is stimulated by long nights and any light interruption during that necessary dark period can delay flowering. Light from a streetlight, interior light, or headlights from a passing car is sufficient to interfere with the flowering process.

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I have a few bushes of plumbago that have been in bloom for months, but I never prune off the old flowers. Is pruning needed to keep them healthy, and can I cut them back when they grow too wild?

While the plants may look messy, the plumbago is a self-cleaning shrub. This means, as the flowers fade, growth hides the declining blooms. Pruning usually is needed only to remove cold damage or to keep the plants in bounds. Many gardeners routinely prune their plants, but this practice can remove lots of potential flower buds and ruin the natural rounded look of the plants.

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After being planted, the leaves on my hibiscus turned yellow and fell off. I want to try once more. What tips can you give me for success?

Water, water and more water, though the problem may not be a lack of water. It could be that the water that is applied just runs around the root ball without moistening the roots. This is a common problem with many plants.

Hibiscus plants fill their pots with roots and often are pot bound at purchase. Also the soils are organic and hard to wet once they dry. This is a bad combination that sets up the plants for failure unless special care is given at planting time.

Tease the roots of pot-bound plants apart a little. This encourages the new roots to grow into the surrounding soil. Then as planting is completed, create a berm of soil or mulch around the edge of the root ball to catch and direct water down through the root system. Then it's your turn to water by hand frequently to keep the root ball and surrounding soil moist.

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I have a hibiscus bush that needs to be trimmed. When is the time to trim it, and how much?

Trimming to remove out of bounds shoots can be done, anytime, but most gardeners delay major pruning until the cold weather is over in late February.

The plants are still producing attractive flowers which can be enjoyed until frost or freezing weather arrives. When pruning is needed, remove some of the older stems back to the trunk or near the ground. Then cut back the remaining stems to the desired height to begin spring growth.

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I am having no luck finding a gardenia plant that will grow here. Can I start one with a cutting from my neighbor's huge plant?

Rooting the cutting is easy, but getting the gardenia to survive in the landscape would be difficult. Most gardenias are susceptible to nematodes living in home soils. Purchasing a grafted plant with a nematode-resistant rootstock is still the best way to ensure success. Check the garden centers after the first of the year for the varieties like Coral Gables, Glazerii and Miami Supreme that always give a good spring performance.

Planting is just the start to a health and well-flowered gardenia. The plants like to stay moist and usually need special waterings once or twice week during the dry times. Also maintain a 3 to 4-inch mulch to help keep the soil moist. Feed the gardenias once monthly in March, June and October with a general garden fertilizer. And finally, keep the scale insects under control with an oil spray as needed.

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I have a hedge of sweet viburnum that has grown to about 6 feet tall and is leggy. Would the plants survive being cut back a couple of feet?

Viburnum are tough, durable plants, but now may not be the time to prune. It's probably best the plants are given a chance to discontinue growth for the winter. This helps make them resistant to sudden bursts of cold. Wait until mid-February to prune the hedge severely, and you can chop away without harming the plants.

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Our neighbor's oak fell during the hurricane and left a big sun spot in our yard where we are trying to grow hydrangeas, flamingo plants and bromeliads. It will be a while before our anise shrubs can grow tall enough to shade these plants. What can we do in the meantime?

None of these plants are going to like the sunny conditions. Only the hydrangeas could exist in the sun if they have a constantly moist soil. You have two choices to protect the remaining plants: Remove them or create overhead shade.

Maybe the plants could be transferred to containers and grown in a protected area until the anise shrubs provide shade. If you wish, the plants could be transplanted to another part of the landscape that already has lower light levels.

The other option is to create overhead shade with a screenlike cloth. Grower supply stores have shade cloth that is used by the foliage plant industry. The' cloth could be stretched between poles to reduce the light level until natural shade is available. You also could build a pergola or similar structure over the plants.

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Two gardenias I planted a month ago are growing well, but dropping leaves, and one is dropping buds before opening. What is needed?

Newly planted trees and shrubs show symptoms of transplant shock when this happens. Also it's late in the season for gardenias to be blooming, so some of bud drop is normal.

Make sure the root ball remains moist by building a 4 to 6" berm of soil to trap water. Feed every 4 to 6 weeks to maintain growth with a good gardenia fertilizer.

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I have two butterfly bushes that have grown too tall and wide for my patio. When and how do I cut them back?

Remove limbs that are hanging over walkways and encroaching on other plants, but delay the major trimming until late winter. A freeze may do some of the trimming for you, and by the end of February you can determine what needs pruning. Trim out the cold damage and any other limbs needed to restore the bush to the size and shape you want.

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I have one camellia bush that gives buds each year, but do not mature into blossoms. Do I need another bush?

You do need another bush but not to help bring this one into bloom. Your camellia variety is likely a late-maturing selection. These seldom open their flower buds before the spring growth begins. This causes them to turn brown and drop from the plant. Either hope for an extended cold winter, or replace with another camellia variety that flowers early to mid-season.

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My bougainvillea was starting to bloom when it was damaged by cold. It was cut back last spring. Now it produces only green shoots in spite of good feedings and adequate water. When will it flower again?

The main flowering time is late winter through spring. Many plants flower only at this time. Some newer varieties produce more flowers throughout the summer. Plants that have been damaged by cold and pruned can be expected to produce lots of new shoots and no flowers for several seasons. The plants have to reach maturity before new blooms form. This should be in time for late-winter flowering.

Reduce feedings to once in the spring and early summer. Also water only during periods of severe drought. Complete all pruning by midsummer. Minimal care encourages periods of extended blooms.

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We have a bird of paradise that has been healthy and growing for 10 years, but it never has produced a blossom. Is there an explanation for the lack of flowers?

You have been patient for the past 10 years, but now it' s time for a discussion with your plant. Cut off the free food and put it on a low water diet. Most nonflowering bird of paradise plants quickly shape up.

It may seem a bit abusive, but water only during periods of severe drought. Also, lightly apply blossom-booster type fertilizers once monthly in March, June and September. Make sure the plant has a full-sun to lightly shaded location and a 3 to 4-inch layer of mulch over the root system.

Get tough, and you should get blooms within a few months.

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We moved a bougainvillea to a new site about two years ago. It has lost most of its leaves, and has only a few flowers. Is this transplant shock, and should we keep the plant?

It sounds like transplant shock and some care problems. Give the bougainvillea another year of good care before removing the plant. If needed, trim to reshape the plant: then start a regular maintenance program. Keep the soil moist and feed lightly every six to eight weeks to stimulate growth. When the plant produces the growth needed, reduce the feedings to once or twice a year, and water only during periods of drought.

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I have a grafted gardenia that is 4 feet tall. It's as high as I want it, but not as dense. When it finishes flowering, can I cut it back about a foot to help it produce more branches?

Four feet is not very tall for gardenias that commonly grow 6 feet or more in height. Keeping the plants smaller in height and width may result in few and smaller blooms, but it can be done. The frequent pruning that's needed to keep the plant compact also may produce a boxy look.

It's best to remove the longer branches selectively and avoid shearing to produce a plant with a natural rounded appearance. When you have reduced the size by a foot, trim the tips of the remaining branches to encourage shoots. Allow these shoots to grow 6 inches or more, and then cut out the tips again to cause additional branching.

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We have a desert rose growing in a container that is yellowing and losing leaves. How can I revive this plant?

Lots of warm weather and sun should bring this plant back to life. The desert rose reacts to cold by shedding its leaves. Find a sunny spot for this plant. Water when the surface of the soil begins to dry. The desert rose is drought tolerant, but the lack of water during the hotter months also can cause the leaves to yellow and drop.

Feed the plant with a houseplant fertilizer every other week Spring through early Fall, or apply a slow-release fertilizer following label instructions. Also stay alert to white scale insects, and control with an oil spray if needed.

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My bougainvillea does not get red blossoms any more. What can I do to make it attractive again?

Yours is just one of many questions from frustrated bougainvillea growers. First, the major flowering time for these vining shrubs is late winter. This is the best time to observe the blooms that are really modified leaves.

Help bring out the late winter color by allowing the plants to grow to full size. Too often gardeners keep the plants as small shrubs by pruning, which stimulates stems and leaves with few flowers. Complete all pruning by late summer.

Next, keep feedings to a minimum. Normally a feeding with a general garden fertilizer once in March and once in June is all that is needed. Also let the rains do the watering. The bougainvillea is drought-tolerant and can be coaxed into bloom by withholding water.

Growing bougainvillea in containers is another way to encourage blooms. Often these stressed plants bloom throughout the year.

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I have a bed with seven roses; four are doing well; three are losing color in their leaves and appear to be declining. They've had good water and fertilizer: What should I do?

Sometimes it's best to add a few new plants. Most likely the declining roses have root and stem problems. You might notice some browning in the stems that suggests a fungus is at work.

When the decline is affecting a major portion of the plant, it's time for a new rose. Remove the plant and some of the soil within the root zone. Till the remaining soil deeply, and then add soil and organic matter. Then replant and give the new rose normal care.

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I have a ligustrum hedge that has grown several feet over a sidewalk and is more than 10 feet tall. Can I reduce the height and width of the planting without causing it harm?

Your hedge may look a little twiggy for a few months, but a severe trimming shouldn't harm it. However, the recovery is going to be slow because of the cooler weather. Most gardeners prefer to delay the trimming until early February when the plants start growing.

It's probably best to trim the hedge a foot or two less than the height and width you would like it to be. As the shoots grow to about 6 inches, cut the tips to encourage branching. Then allow 6 inches of growth and cut this back to leave 2 inches of growth. Continue doing this to allow a full but in bounds hedge to develop.

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My gardenias have grown very little the past two years. I water and feed them, but the leaves are yellowing and dropping off. What should I do?

Dig down into the soil and check the roots. Most likely, the plants have a limited root system due to minimal growth from their root balls. You can try to encourage better growth this spring by keeping the soil moist and providing light but frequent feeding, but it may be futile.

If the plants are not sending out lots of new shoots by summer, they will have to be lifted and reset. This time, break apart a portion of the root system to encourage growth into the surrounding soil. With such disturbing treatment, there is a risk you may lose the plants, but it's probably your only way to get them to grow.

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I have a beautiful large selloum philodendron that keeps growing taller and wider. It's blocking a view and interfering with lowergrowing plants. Can I remove the lower leaves or trim the plant?

Selloum are tropical-looking plants. Often called tree philodendrons, they grow to more than 8 feet tall. If the plants are healthy, you can trim them any way you want. It might be possible to remove some of the lower leaves to expose a view. If needed, the plants could be cut back rather severely to expose plants in the background. Shoots will grow from the thick stems to form a new plant in time. You might consider relocating this plant.

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The leaves on several of my hibiscus are turning yellow. What can I do to help the plants?

The winter weather was cold enough to affect the leaves of the hibiscus plants but not to cause severe stem injury. Many of the leaves may be lost, but the plants will swell the buds to form the replacement foliage.

Now that the stems are a bit barren, it may be a good time to prune to remove the lanky growths and some of the older nonproductive shoots. Otherwise, feed the hibiscus and keep the soil moist to encourage leaf growth.

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I bought several oleander plants a week ago that had a few yellow leaves. Now that they are in the ground, they are developing more yellow leaves. Should I be concerned?

Oleanders periodically change out their leaves and some yellow portions are often normal. Excessive yellowing does occur if the plants are too dry. Because your plants are new, dig down and check the root balls of several plants to make sure they are staying moist. Often when plants are set in the ground, the water runs around the outside of the root ball and the foliage exhibits signs of drought that could include yellowing leaves.

It may be hard to believe, but plants can remain dry even during rains and with irrigation until the roots grow into the surrounding soil. If the root balls are dry, build a berm of soil 4 to 6 inches high around the edge of the root ball. Then water daily so the water has to run through the root ball and out into the surrounding soil.

Keep the plants on this schedule for several weeks; then gradually reduce watering to every two or three days until established

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I have a gardenia bush that needs trimming. How can I root the shoots? I have had good luck rooting other plants but not gardenias.

Woody plants that include gardenia are a bit more difficult to root than houseplants and perennials. Start by making cuttings 4 to 6 inches long from the shoot tips. Dip the cut ends into rooting powder available from your garden center. Then insert the bottom end of the cutting an inch or two into a pot of moist vermiculite.

The real trick to rooting cuttings is keeping them moist. Surround the pot of cuttings with plastic and set in a shady spot. Keep the foliage moist by misting the cuttings several times a day. Usually the cuttings root in 10 to 12 weeks. When clusters of roots 3 to 4 inches long form, they are ready to transplant to individual containers.

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I grew up in New York and was wondering whether lilacs grow in the Orlando area? I have not seen any locally.

If it was possible to grow lilacs locally, most gardeners would have one or more plants in their Shrub. Like you, many relocated gardeners have fond memories of this plant, but it does not receive the cold needed in Florida to begin normal growth and flowering during spring and summer.

Possibly the lilac of the South would be a good substitute. Most know this plant by another common name - the crape myrtle. Though it's missing the fragrance you remember, the color selection is equally pleasing, and it can be in bloom May through early October.

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We have a large bird of paradise plant with crowded stems. There are also yellow and white spots on the leaves. Should we cut back the plant, and does it need a spray?

Because of the size of your plant, it is most likely the white bird of paradise species. These do grow quite tall and wide. There is no good way to keep them in bounds; they are just big plants.

If needed, you can selectively take out the taller shoots, but then you also remove flower buds. The plants can have sections removed from the sides to keep them more compact. Possibly this is the wrong plant for your landscape site. You might consider replacing it with the much smaller orange-flowered bird of paradise selection to keep the same look.

The yellow spots noted are produced by a white scale insect that lives on the foliage. The white insect bodies can be rubbed off to expose the yellowing plant tissue below. Where needed apply an oil spray to obtain control. Follow label instructions.

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What is the secret to growing gardenias? I add new plants to the landscape, and they decline within a year.

Gardenias do need fairly constant care to survive. Start with grafted plants and give them a full-sun to lightly shaded location. The plants need a fair amount of water. Keep the soil moist with frequent waterings, especially in the hotter spots. Also, maintain a 3- to 4-inch mulch layer over the root systems.

Feed gardenias with a general garden fertilizer once monthly in March, May, August and October. Just a light scattering of fertilizer over the surface of the mulch is adequate. Sometimes the plants develop prematurely yellow leaves because of a magnesium deficiency. This can be corrected using products containing magnesium sulfate or Epsom salts. Follow label instructions.

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We planted several viburnums last year to create a hedge along our property. They looked good until spring when they dropped lots of leaves and did not produce many more. What is the problem?

First check to make sure the hedge is growing in a sunny location. Viburnums in too much shade do develop an open habit with limited new growth. Also make sure the plants are in a well-drained but moist site and receive several feedings a year to encourage growth and new leaves.

Next look for leaf spot problems. Recently viburnums have been affected by a downy mildew fungus that causes brown areas in the leaves with yellowing and eventual loss of the affected foliage. The plants may lose vigor and not regrow as rapidly. If leaf spot appears to be the problem a mancozeb-containing fungicide available from local garden centers can help prevent further decline.

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One of my crape myrtles planted last year has developed brown tips at the ends of the leaves. I have seen others with the same problem. What is the cause, and can it be corrected?

Most likely you are seeing the effects of a water problem. If the crape myrtle gets too much water, the roots rot. If the root system is not extensive enough, the crape myrtle cannot take up the needed water to maintain the leaves during the hot summer months.

Most plants showing these symptoms recover and resume the root growth needed to produce the more attractive foliage another year.

Many crape myrtles are also exhibiting leaf discoloration because of a lack of fertilizer late in the growing season. These plants are heavy feeders and need applications once monthly in March, June and August for best growth and flowering. Otherwise, leaves often turn an orange to red color and drop prematurely by late summer.

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We recently purchased a bird of paradise plant for our landscape with lots of green leaves. How do we keep it healthy and promote blooms?

Most bird of paradise plants need time to get accustomed to their new home and to grow before beginning to flower. Even if they are flowering when planted, they may stop blooming for a year or more.

Help your plant become established and restart the flowering process by giving it a sunny to lightly shaded location in a well-drained soil. Keep the soil moist, and add a 2- to 3-inch mulch layer to cover the root system.

Feed lightly with a general garden fertilizer every six to eight weeks April through September. After a year or two of good growth, reduce the feedings to once monthly in March, June and September to slow growth and encourage blooms.

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I am planting dwarf azaleas under an oak tree where they receive mainly shade until midday; then they are in the sun. Will this location be suitable, and what is the best spacing for the plants?

Your azaleas may survive, but don't expect them to be happy in the afternoon sun. Azaleas prefer a full day of filtered sun or early morning sun and then shade. Maybe you can reposition the planting to provide more shade. Otherwise, you can expect plants in the hot afternoon sun to be difficult to establish, to need more water and to assume a yellow-green appearance.

Plant spacing depends on the ultimate size of the selection. Even among dwarf selections there are wide size variations. Ask the garden center about the expected width of your plants.

Then space them according to the mature width minus 1 foot if you want the plants to overlap at maturity.

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Many of my rose bushes declined during summer and fall. When can I trim the dead branches?

The sooner the better is the rule when it comes to removing dead stems and major limb from any plant.

It's best to do a little grooming whenever you visit the rose garden. This includes trimming declining flowers, lanky shoots and dead plant portions.

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I am about to prune my ixoras heavily. Can I use hedge shears or is it best to remove individual branches?

Ixoras won't mind a one-time heavy pruning with hedge shears or a pair of hand clippers. The question is how do you want the plant to look? Hedge shears give the plants a formal look that requires frequent maintenance.

Many gardeners are trading in their shears for hand pruners to remove unwanted stems that allow the plants to keep a natural shape. These plants respond with more uniform growth that requires less maintenance to keep their rounded open habit.

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We cut back our hibiscus several months ago, and since then there have been no flower buds. Is this normal?

Your plants are quite normal. After heavy pruning or significant cold damage, the plants go into a growth phase where only shoots and leaves are produced. This may continue for several months. During the growth, keep the soil moist and feed lightly with a low-nitrogen, blossom-booster type fertilizer.

Around early to midsummer the plants should start to produce flower buds. Reduce waterings to only during periods of drought and restrict feedings to every three to four months. Also, prune only shoots that are out of bounds or lanky.

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I purchased a small camellia with a tag that showed a plant with a red flower. Now that it's blooming, the flower is white. What do you think happened?

One good guess is a gremlin switched the tags at the nursery or garden center. Or maybe a cutting from a white plant ended up with-those from some red ones during rooting. No matter what, you are probably the owner of a beautiful white camellia.

If just one branch bears white flowers, there may be another cause for the difference in color. Camellias are known to produce mutations, often called sports, that result in branches with different-colored blossoms. Growers often use these sports to propagate some of the newer varieties.

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Our oleanders have grown tall and are flowering. When is the best time to prune?

Normally, cold weather damages the more-sensitive shrubs, and pruning amounts to removal of the declining portions.

This year Mother Nature didn't help with the pruning, so it's up to YOU to decide when and how much trimming is needed.

If your plants have a good shape and are not too large for the landscape, little or no pruning may be needed. You might just remove some of the older stems.

Certainly remove any damaged portions or those that appear to have pest problems. Longer shoots could be tipped back to en. courage branching and more blooms at a later date.

If your plants are overgrown or out of bounds, a severe trimming to within a few feet of the ground may be needed. This year you get to make the decision what to prune, but the sooner the better.

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This is my first time growing roses. My friend says they are a cinch to grow as long as I feed them and provide pest control. Will they grow in full sun, and what care is needed?

Roses are fun to grow and can provide lots of bouquets, but your friend makes the care sound easy. First give roses a full-sun location to produce the best growth and lots of flowers. Also feed the plants monthly with a general garden fertilizer or one of the special rose products following label instructions. Also keep the soil moist and maintain a 3 to 4 inch mulch layer over the roots.

As your friend noted, pests can be a major problem. Try to find rose varieties that have the most disease resistance. Ask for roses that resist powdery mildew and black spot, and you may never have to apply a fungicide; otherwise, sprays may be needed every week or two.

Several roses that are good pest-free selections for a beginner are "Belinda's Dream", "Knock Out" and "Louis Philippe", but there are many more. You will have to control mites on most roses during the drier spring and fall months. Use a natural oil spray when these pests are noted, following the label instructions.

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We have shrubs along the front of our home that have grown too tall. Is there a proper time to prune our bushes?

Pruning time depends on the flowering habits of the shrubs. Delay pruning until after the major blooming time is over for shrubs that flower dur. ing winter or early spring. These include azaleas, gardenias and camellias.

Others, including crape myrtles, thryallis and hibiscus, should be pruned toward the end of winter just before growth begins.

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A friend is thinking of adding a climbing rose to a fence. Can you recommend a variety? Should it be trained to the fence or a trellis?

If you have space for only one climbing rose, make it a Don Juan with, bright red flowers and good pest resistance. Other choices include Altissimo, America, Cherokee, Sea Foam, Sombreuil and Yellow Lady Banks. It should be happy trained to the fence; climbing roses need infrequent pruning.

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A friend brings me beautiful camellia flowers and says I can add them to my landscape too. Are they difficult to grow? Where is the best location for the plants?

Camellias are one of the best winter-flowering plants; they can be in bloom from November through early March. When selecting a variety, pick early to midseason flowering types that are known to be good performers locally. Starter selections should include the older reliable varieties of Alba Plena, Professor C.S. Sargent, Mathotiana Rubra and Debutante, which are still available at garden centers.

Probably the best site for camellias is a filtered-sun location. Areas with morning sun and afternoon shade are fine too. Many can tolerate full sun, but they will need a lot more water, and the leaves will be a bit yellow. Also check to make sure the plants are not pot bound when purchased. A camellia with a tightly woven root ball is less likely to become established.

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We bought a house with azalea bushes that are about 5 feet tall. After they bloom, can we prune them to about 3 feet? There are no leaves, just branches at that point.

Healthy azaleas can withstand an occasional severe pruning. Even though there are no leaves at the 3-foot mark, there are plenty of buds waiting to sprout when the tops are removed. If you wish, the plants could be pruned even closer to the ground to get a fresh start.

During pruning, look for injured or declining wood to remove to the ground. Older azalea stems often develop dead areas that if not removed continue to decline down into the crown at the soil line. When this occurs, the entire plant may die.

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I have two bird of paradise plants that get regular feedings and water but bloomed only once in three years. My parents have a plant that blooms frequently with little care. What am I doing wrong?

Maybe you need to take a tip from your parents this time. Bird of paradise plants love the good life and with lots of water and fertilizer grow lots of leaves and few flowers. It's time to put your plant on a lean diet of feedings once or twice a year in spring and early summer plus water only during the dry times. This benign neglect should pop out the color within a year.

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We have a white bird of paradise plant that has spent this year recovering from cold damage. It gets good care. When can we expect blooms?

Bird of paradise plants are reputedly slow growers. Cold winter damage can delay flowering for several years as the plant grows new stems and leaves. Limit watering and care as needed.

Sometimes too much care encourages growth at the expense of flowers. Water during periods of drought and maintain a 3 - 4 " layer of mulch over the roots. Feed lightly once per month in March, June, and September with a low nitrogen blossom-booster type fertilizer, then hope for a few warm winters.

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When is the best time to divide a bird of paradise? Do you need to dig up the whole plant or just thin it out?

Bird of paradise can be divided any time. If dividing during the cooler months, don't expect a lot of growth until spring, but the plant can still begin establishing roots.

You have the option of digging the entire plant and separating it into sections with three or more main stems, or severing sections from the parent planting, while the rest remains in the soil. The plants are firmly attached, so you need a sharp pointed shovel or knife to do the dividing. Keep the plants moist after separating, and if the weather remains warm, feed them in four to six weeks.

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I planted several dwarf gardenias a few weeks ago. Each one is developing yellow leaves. They get good care. What is wrong?

For each to be declining at the same time, there has to be some cultural problem, and most likely, it's a lack of water. Even though you water frequently, the water might be missing the mark by running around the outside of the root ball. Dig down and take a look; if the root balls are dry, you have found the problem.

Perhaps the best way to help the plants recover is to lift them and put them back in their original containers where they can get the water they need. When they recover, add them to the landscape, but this time create a berm around the root ball so water can be directed through the root system and into the surrounding soil.

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I have an orange-flowered bird of paradise plant on my patio that is in bloom. Will it hurt to prune old leaves? Where should I make the cuts?

Broad-bladed bird of paradise leaves are supported by long, stemlike portions called petioles. When the leaves are damaged or turn brown, remove the entire leaf and petiole back to the trunk of the plant normally near the ground. Make the cut flush with the base ofthe plant.

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We have several large plumerias that we can no longer move into the garage; so we planted them in the ground. What will happen to them during the winter? What should we do to protect them?

Hope for a warm winter and your plumeria plants, also called frangipani, could be unharmed survivors. More realistically, however, these are cold-sensitive plants that certainly would be damaged by freezing temperatures. Perhaps it is best to have a cold-protection plan.

You might try draping cloths over the plants to the ground on really cold nights. This could be enough to hold in warm air and keep cold air out. More-determined gardeners might build a wood frame around and over the plants to enclose with plastic when the cold warnings are sounded. If more heat is needed, light bulbs could be added to keep the temperature inside above freezing.

Some gardeners try turning on water to form an ice layer over the plants. But unless you can keep the ice forming uniformly over the plants for the entire cold period, it seldom works. This treatment often results in more freeze and structural damage to the plants than if you did nothing.

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I added four hibiscus plants to the landscape last spring. I pruned a few long shoots but don't want to do too much while they are flowering. Can they tolerate a severe pruning? If so, when?

Hibiscus plants are still in full bloom and should continue to open buds until the first frosts or freezes of winter. If you can, delay pruning until late February when cold weather is usually over. Then you can trim the plants severely if needed.

The plants can be cut back a foot or so above the soil. Most gardeners, however, remove only a few of the older shoots and trim back stronger, healthy ones a few feet below the desired height so as not to delay the spring and summer blooms.

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A friend gave me two container-grown bird of paradise plants that I added to the landscape six months ago. My friend said they never bloomed, and they have not produced a blossom for me either. Is there a secret to getting the plants to flower?

Some things just take time, and bringing a bird of paradise into flower is one of them. First, make sure the plants have a sunny site. They need about three years to become established in a new location and to get into the flowering mode.

You can help by keeping the soil moist and feeding the plants lightly every six to eight weeks for the first two years with a general garden fertilizer during the warmer months.

At year three, put the plants on a leaner diet. Don't let the plants continue to enjoy the good life, or they might grow foliage forever. Restrict waterings to the dry times, but maintain a 3 to 4 inch mulch over the root system. Also, keep feedings to once monthly in March, June and September using a low-nitrogen, blossomboosting product. The plants should get the idea and soon start to pop out the flowers you are waiting to enjoy.

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Each spring I trim the Philippine violet shrubs close to the ground, but, by flowering time in the fall, they are tall and lanky. Could I trim them during the summer months to keep them more compact?

Philippine violets, also called bluebell barleria, are a welcome addition to the late-summer and fall garden. Shortening summer days brings them into bloom, with white, pink or purple blossoms, but this should not discourage you from giving them a midseason trim. Make sure the plants are pruned the way you want them by the end of July so the shrubs have time to form their flower buds by fall.

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All of a sudden, my beautiful Formosa azaleas are getting dark spots on the leaves, which also have a white look to them. My neighbor said it is a fungus. I've treated the plants, but they still look bad. Now what?

Give your neighbor at least half-credit. The dark spots are likely the cercospora leaf spot fungus that often shows up to mar the foliage after a hot and moist summer. When you see the spots, it's usually too late to stop much of the damage. Perhaps you can anticipate the fungus infestation next year and make the fungicide application in August or early September to prevent the return.

The white to yellowish appearance to the leaves is caused by lacebugs. Turn the leaves over, and if you see dark spots on the updersides of the leaves, it's likely the insects sucking juices from the foliage.

These pests can be controlled with an oil spray or an insecticide that contains Merit or one of the new synthetic pyrethroids available from your garden center.

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I have several snowbushes that have grown too tall and wide. I have been told to cut them back in fall and spring. Is this right?

Most likely the bushes won't care when you prune, but you might want the attractive green, white and red foliage to decorate your landscape during fall and winter. If pruned now, when it's cool, the recovery could be slow; the plants grow best during warmer weather.

Snowbushes are cold-sensitive; so you can expect frost or freeze damage during even the mildest winters. Perhaps it's best to wait until the end of February to remove older stems and cut back the plants to within a few feet of the ground.

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I think my gardenia needs to be pruned. How do you know when to trim these plants and how much?

Make your pruning decisions after the plants have produced their midspring display of flowers. The buds are forming now, and it would be a shame to miss their fragrant white blossoms.

You could remove any branch that's in the way of traffic or appears to be declining at anytime. Major pruning usually occurs around May or June when spring flowering is over.

Then the plants might get a light trimming to encourage additional shoots and reduce the height and width just a bit..

Gardenias can be large plants, and most gardeners place them where they can grow with minimal pruning.

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I have a healthy corn plant that is getting ready to bloom. Is this a sign it could be dying?

Some plants do decline after flowering but not the corn plant, a tropical foliage plant, also known as a dracaena. The blooms are a bonus for the good care you have been giving the plant.

Corn plants flower only if growing in bright locations but out of direct sun. Most likely, you also have been keeping the soil moist, and feeding the plants every month or two, which also makes them happy.

Now, when the flowers open, you might get a surprise. They are fragrant, resembling a super-sweet gardenia, but some gardeners find the blooms objectionable. If needed, the flowering stalk can be cut from the corn plant or the plant can be moved to a more airy location.

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I have a 6-foot-tall bird of paradise in front of my house that blooms fine, but its leaves and stems are interfering with other plants. Can I cut it back? If so, when?

Pruning probably won't be the answer to your out-of-bounds problem. Bird of paradise plants are naturally tall- and wide-growing plants. You can cut off a few leaves if you wish, but the plant usually responds with another flush of tall- and wide-growing shoots. Perhaps the best answer is either to divide the plant or move it to a location where it has additional room to grow.

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I received a hyacinth forcing kit as a gift that says to chill the bulbs for six to eight weeks at 40 to 45 degrees. Can we set them outside for the cold treatment?

Such a cold treatment needs consistent chilly temperatures to bring the bulbs into bloom, and Florida's weather might fluctuate too much. The best spot to give them the needed cold is in the refrigerator.

First, place the bulbs in a paper bag and set it in the refrigerator. After the cold treatment, follow the remaining instructions using the special hyacinth vases that came with the kit.

This allows the base of the bulbs to sit in water while they are coming into bloom.

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I recently added ligustrum trees to my landscape. Now some of the leaves are yellow, and a few have brown spots. Should I be concerned?

Most gardeners see brown and yellow spots on their ligustrum trees. The plants seem to have a close association with the cercospora leaf spot fungus. Usually the fungus lives hidden among the lower leaves and seldom is noticed. But when growth slows because of transplanting or limited care, the fungus gets ahead of new leaf production.

Some yellowing and spotting is normal and can be tolerated. It should be covered up by springtime growth. Make sure your new ligustrums have adequate water and light feedings every other month the first year to produce new leaves. If needed, a fungicide labeled for leaf spot control could be applied to help the ligustrums get ahead of the fungus.

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Three weeks ago, I transplanted 12 azaleas from containers and now notice some of the leaves are turning yellow even though I water them every other day. What should I do?

Some yellow leaves are normal on all azaleas at this time of the year, but this planting also might have dry soil. Even though you seem to be providing adequate water, dig down and check the root balls. Pull a portion of the root ball apart, and reach inside to feel the soil. Often, water runs around the outside of the root balls, and the plants are left too dry. This results in the yellow leaves.

If the root balls are dry, build a berm of soil around the outer edges of each to capture the water and direct it down through the root systems. Then begin watering by hand for a few weeks before returning to watering every two to three days.

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My hibiscus were once dense, but now they have lost most of their leaves, and the plants look spindly. What can I do to restore their beauty?

Hibiscus and the dry winter weather have not mixed well this year. Most likely, much of the yellow foliage and leaf droll noticed in local landscapes are because the soil is dry. Also, cool weather might be responsible for some of the yellowing.

Now might be the best time to prune thin and unproductive shoots from hibiscus plants and remove older, damaged stems. Reduce the plants to a height and width you can live with for another year. Check the soil for moisture, and water as needed to encourage growth.

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We have a camellia that was planted in the shade about four years ago when it was about 18 inches tall. It has not grown one bit. We are thinking about transplanting it to another area. Is this a good time?

Most likely, your plant remains pot-bound. This is a common camellia problem in which plants are set in the ground without altering their tightly wound root balls. Transplanting now might save its life.

Lift the plant from the soil, and check the root ball. If the roots are entwined, pull them apart to encourage their growth into the surrounding soil. Also, try to find a filtered sun location preferred by camellias. Keep the soil moist, and your small plant could sprout new healthy shoots for spring.

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I have a frangipani about 3 feet tall that is growing in a container. Is it too late to plant it in the ground?

Frangipani plants, also called plumerias, don't like the cold, so why not do your plant a favor and keep it in a container for one more winter? When spring anives, it can be given a more permanent home in a warm location. A spot on the southeast side of the home might be best.

An option is to continue growing your plant in a container and transplanting to a bigger container as the plant grows larger. Many gardeners do and then move their container-grown plants to a warm location when damaging cold is expected.

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I have a container-grown hydrangea I would like to transfer to the yard. Where is the best location, and do I add nutrients at the time of planting?

Skip the extra nutrients, but find this plant a spot with morning sun and afternoon shade. An area with filtered sun all day long also would be a good location. Care after it has been set in the ground is important, too. Most of all, keep the soil moist. These plants use lots of water, especially during hot, dry times.

Also, add 3 to 4 inches of mulch over the root system, but keep it back several inches from the main stems. You can feed the hydrangea once monthly in March, June, August and October using a light application of a general garden fertilizer.

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