Landscape Horticulture — Annuals and Perennials

 

I received a box of tulips from a friend up North. How difficult are they to grow locally?

It's not impossible, but it's a lot of work to get tulips, hyacinths and most daffodils to bloom in Central Florida. They need more cold than the normal winter can provide; so you have to give them a refrigeration treatment.

Some residents have luck tossing the bags of bulbs in the refrigerator for about three months and then planting them in the ground. Others are more successful if they plant the bulbs in containers and then store them in the cold. There is also one little problem.

You cannot store fruits or vegetables in the refrigerator at the same time. These edibles give off a gas that causes flower buds within the bulbs to abort.

Gardeners who are serious about preparing bulbs for planting winter displays need a separate refrigerator. You can plant the bulbs in small pots or peat containers. Then keep them moist and in the cold for 12 weeks. After the cold treatment, they can be planted in the ground, and they usually bloom within four to six weeks.

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Two of my Queen's Tears have not bloomed but are producing numerous pups. Should they be removed?

If the pot is big enough, you can allow the new shoots to continue growth around the mother plant. This bromeliad grows well in a cluster, and a number of shoots flowering at the same time adds to its beauty. Move the plant to a bigger pot when necessary.

You can also form new plants from the pups, but wait until they are 6 - 8" tall, and then snap them from the mother plant.

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When is the best time to transplant my plants?

Container plants can be planted any time of the year. The critical factor is keeping the root ball moist for several weeks to several months after planting. The dormant period of the year is the best time to dig and move plants that are existing in the landscape. The next best time is just after a growth flush has hardened off. Plants that are root pruned 6-10 weeks before moving, then dug just beyond the root-pruned area may survive better than unpruned plants.

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My canna plants are turning yellow and declining. What is the best way to store the bulbs over the winter?

It's best to leave the rhizomes in the ground. Make sure your plants have adequate water and fertilizer to help them grow until the cold weather arrives. When temperatures drop into the low 40s, check the mulch to make sure the rhizomes are protected from freezing temperatures. Leave potted plants outdoors until a freeze is expected. Then move to a warm location until the cold weather is over.

If you need to dig up the rhizomes, remove them and allow to air-dry for a few days. Then remove the adhering soil and place them in a box with peat moss or vermiculite to stay dry. Store them in a cool, dry spot until spring planting time.

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We have a bank near the house that is shady. Is there a good ground cover that will prevent erosion?

The incline and shade won't be a problem for Asiatic jasmine, also known as the small-leaf Confederate jasmine. Varieties with several leaf shapes are available at garden centers. Some also have reddish and cream leaf colors. Space the plants 2 to 3' apart.

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We have a narrow area along a front walk with a southwestern exposure where nothing seems to survive. We would like permanent flowering plants. What would you suggest?

This is going to be a hot spot, but there are some tough, durable and low-growing plants you might try. Suggestions include false heather, Mexican petunia, bush daisy, dwarf penta, lantana and whirling butterflies. These do need care during early growth. Being a difficult area, add a thin layer of mulch and keep the soil moist until the plants grow roots into the soil.

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Should I rough up or cut the roots of pot-bound annuals as they are planted?

Try not to purchase annuals or other plants that are pot-bound. Most make poor root growth or are slow to recover after you untangle the roots. Before you buy, tap the plant out of the pot. If the roots are tightly wound, try another plant.

Plants with a loose network of roots can be added to the ground with no disturbance. If the roots are starting to hide the soil, it's best to pull them apart to allow them to begin growth in the garden.

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I have a jade plant that is beginning to develop a green mold on the surface of the soil. Is this a problem?

The green growth is likely algae or moss. Neither harms the plant, but a sheet of algae could prevent water from entering the soil. Moss however, does allow water to penetrate. If either appears to be a problem, scrape it off and add new soil. Growth of algae or moss could mean that your plant is being over-watered. Jade plants are succulents that grow best when the surface of the soil dries between waterings. Keeping the plants too moist can lead to root rot. Also the plants like to be pot bound which insures rapid water use to prevent problems.

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My amaryllis plants have brown portions on the leaves, and some are flopping over onto the walkway. Can they be trimmed now?

When amaryllis leaves get ugly or grow out of control, it's time to prune. They can be trimmed back to within a few inches of the top of the bulb around February. Some gardeners say winter trimming increases flower production.

It's probably the rest period experienced during colder weather that in creases blooms.

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I received a large peace lily. I divided it, removed most of the soil from the roots, and gave each new plant a large container. The plant now has drooping leaves and appears to be in shock. What should I do?

No doubt transplanting was a shock to your peace lily. Removing the soil from the roots likely damaged many of the small water-absorbing root portions. The drooping foliage suggests the plant has a limited root system.

Help the plant recover by watering only as necessary to keep the soil moist. Too much watering can keep the soil wet and encourage root rot. Transplant each plant to a pot that just contains the root system.

The plant should recover when the weather warms. Keep the peace lily in bright light but out of direct sun. New shoots should replace the declining leaves during spring.

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I have a lovely poinsettia that has been blooming for years. Last year it produced only a few blooms. I fertilize it monthly and know I should cut it back this month. How much should I cut back?

The end of August through the first week or two of September is the last time to prune poinsettias and have blooms for the holidays. Most gardeners give their plants a light pruning, removing just the top 2 to 4 inches of each new shoot. The final pruning should help increase the number of blooms.     

Keep the plants on schedule to produce the holiday flowers by maintaining a moist soil and feeding monthly with a general garden fertilizer through November. Plants should have no nighttime light starting in mid-October. Even a porch or streetlight can delay or inhibit flowering

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We planted double ruffle hollyhocks during the spring and have not seen a flower. What can we do to make them flower?

Hollyhocks are usually grown as biennials. Most need a year of growth and then a period of cold to initiate flowering the following year. Many of the plants do not survive the first summer of growth during the hot rainy weather.

If you want to try hollyhocks, start the seeds during October or November so the plants grow and then pass through the needed cold during the winter. This sometimes tricks the plants and they bloom during the spring.

Some local gardeners have found seeds of certain varieties that are saved from year to year and shared with friends. You might try to find someone who has been successful in your neighborhood and ask for a few seeds.

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I have a clivia that forms flower buds that appear to be stuck between the leaves. Last year I could see the orange blooms, but they did not develop full-size flowers. What should I do?

The poor flowering appears to be a maturity problem that clivias, also called kaffir lilies, outgrow in time. The best way to prevent the production of poorly developed blooms is to give the plants good care.

Grow the plant in a shady to filtered sun location, and protect it from temperatures that dip below freezing. Keep the soil moist during the warmer months and on the drier side during the cooler weather. Feed monthly March through October with a 20-20-20 or similar product. No fertilizer is needed during the cooler months.

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I have planted several hollyhocks that have flowered, and the stems are starting to decline. Do I cut the stems down or let them wither?

Keep the garden looking its best by removing the old stems. Do, however, save seeds from the old flower clusters to restart the planting during the fall. Seeds are normally sown in containers during late October or November to have transplants ready for the garden by December or January. Florida hollyhocks are usually treated as annuals, and the plants must experience some cold to flower during late spring.

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Several years ago we installed a bed of agapanthus that bloomed well. Now the plants have only dew blossoms every year. What could be causing the decrease in flowers?

Make sure the older planting has not become too crowded for good growth. Agapanthus bulbs, also known as the lily of the Nile and African lily, multiply rapidly, so it would not take them long to fill a bed. Crowded bulbs decrease in size and need dividing to flower again.

Agapanthus also flowers best in full sun to lightly shaded locations. If nearby trees have grown and produced more shade than they did a few years ago, this could also reduce the blossoms.

Also make sure the soil remains moist during the warmer months and feed lightly once monthly in March, June and September to help force out the blooms.

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I received a phalaenopsis orchid as a gift. It bloomed for several months. The leaves are green, but there is an 18-inch unattractive stem left from where the blooms formed. Can I remove the stem? What care is needed?

The phalaenopsis, also known as the moth orchid, is a durable plant capable of producing new blooms with a little care. If there is no sign of buds along the old stem, it can be removed near the base of the plant. Then locate the orchid in an area with bright light but out of the direct sun to continue growth.

One good spot for the phalaenopsis is in the shade of a tree. You can set it on a table or suspend the plant in a pot from a limb.

Keep the growing medium moist by watering every few days and feeding every other week with a 20-20-20 or similar fertilizer March through November.

When the temperature drops into the 50s, the plant should be moved to a warmer location. Reduce the waterings and discontinue the feedings until spring.

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We planted mums, which started to lose their color and began to wilt within about two weeks. What is wrong with the plants?

Mums are often short-lived additions to the garden. If the plants were in full bloom when purchased, it's possible the flowers would begin to decline in a few weeks. A wilting problem suggests the root ball may have dried, and the plants cannot take up the needed water to continue growth.

One secret to mum survival is buying plants in a bud stage and just starting to show color. These plants gradually open their blooms to display color for four to six weeks. Another secret is to keep the rootballs moist. It's best to water by hand and direct the water toward the base of the plants. Once the root balls dry, they may be difficult to re~moisten, and the plants are often lost or have a short display life.

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My friends said I could have some of their day lilies. When is the best time to divide the plants and add them to the garden?

Day lilies aren't particular about when they are transplanted. Fal1 should be a good time as there is less stress on the plants, and they couId become established before the spring blooming season. Dig a clump and break off a section with several shoots to add to your landscape. If you wish, the tops can be cut back to within about 6 inches of the ground.

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I have a number of amaryllis bulbs in my yard. Can I force these bulbs like the ones available in the stores?

Amaryllis bulbs dug from the landscape can be forced, but you have to give them a short period of rest first. Also be selective and pick plump bulbs that are more likely to have flower buds ready to grow.

Remove the bulbs from the soil, and allow them to air-dry in a shady location for six to eight weeks. Leave the long roots intact, but cut off the remaining green-to-brown top portions just before planting.

Set the bulbs in a container of soil with the necks exposed; keep them moist, and they should flower in about four weeks.

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I have three nicotiana plants that are about 2 months old in a window box that faces east. There is a big tree next to them, so they get about 3 hours of morning sun. Recently one of the flowers started to drop its flowers, and then the leaves started to drop and fall off. What can I do?

Nicotiana, also known as ornamental tobacco, is an annual flower when planted in the landscape. Depending on the size and age of the plants when added to your window box, they may be completing their life cycle. Typically they flower, set seeds and decline.

Your plants are also growing in a light level that is too low for good nicotiana growth. This minimal light level plus heat and rains summer may have hastened the decline. Perhaps the best suggestion is to replace the plants as they decline with begonias, crossandra, impatiens, or torenia that grow better in the lower light areas.

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If I plant petunias and geraniums during the winter, how long can I expect them to last?

Get ready for three to four months of great color from these cool-season favorites. Both produce lots of blooms, but they do need periodic grooming to remain attractive.

It's best to snap the flowers off the geraniums as they begin to fade and pinch or cut off the old petunia blooms.

Plantings need feedings every other week if kept in containers and monthly if grown in the ground. Petunias become lanky with time, but they can be pruned to remove the longer stems. Expect petunias and geraniums to decline during late Mayor June when hot, rainy weather returns.

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My pansies growing in window boxes have been beautiful, but they are now looking somewhat stringy. Can I cut them down and have them start again?

Give your fading pansies a makeover by trimming the longer side shoots originating from the central cluster of foliage near the ground.

Most likely your plants have already initiated new flower-bearing stems to replace those that have started to form seed heads.

Keep the plants moist, and feed them lightly to encourage growth. With this good care, the pansies should last until warmer weather returns around mid-March.

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I want to start a garden from seeds that includes impatiens. When is the best time to plant flower seeds?

Flower seeds can be started year-round in Florida. You do have to pick the best time to sow the seeds for the plants you want to grow.     

Cool-season flowers, including petunias, pansies and snapdragons, are best sown during the fall and early winter months. Warm-season flowers that include impatiens, marigolds, salvia, zinnias and celosia should be planted February through September.     

Few seeds are sown directly in the soil. Florida's sands dry quickly and have a low nutrition level. It's best to plant the seeds in cell packs or small containers. Fill the containers with a potting mix that holds moisture and has nutrients to begin growth. These mixes are pest free to prevent early seedling decline. You also can move the seeded container to a warm location during the cooler spring weather and regulate the light level needed for growth.

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We were given a datura plant and would like to grow it in an area of the landscape that gets filtered sun. Will this be enough sun to get blooms?

Commonly called thornapples, jimsonweeds and sometimes angel's trumpets, the daturas with large white to purplish trumpet-shaped flowers prefer the full-sun locations, but they can tolerate the lower light levels. An area with sun filtering through during the entire day likely will give good growth and flowers. Daturas often are confused with the angel's trumpet, which grow locally as shrubs or small trees. Both are poisonous plants and should be avoided where children and animals might be tempted to taste any portion of the plant.

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I have a fuchsia that is in full bloom. How do I care for the plant during the warmer months?

Fuchsias need cooler weather to remain healthy. It is difficult to keep the plant through late spring and summer to bloom another year.

If you want to try, keep the plant in a cool but sunny to filtered-sun area of the landscape. When the hot and rainy weather arrives, relocate the plant to a filtered-sun location out of the rain.

Fuchsias prefer a moist soil. It's best to water when the surface begins to feel dry. Feed every other week with a 20-20-20 or similar fertilizer following container-plant instructions during the milder weather. When the hot days arrive, feed once a month. With a little luck, you can bring the plant back into bloom during fall and winter.

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About two weeks ago, I planted day lilies that suddenly have begun turning yellow. Do you think this is a water problem?

Day lilies love water. One grower once described them as close relatives of aquatic plants. It would be difficult to overwater plantings in Florida's sandy soils. Day lilies decline when the soil is too dry.

I suggest you dig down in the soil to examine the root balls. Water may be running around the outside of the root balls and leaving the plants dry. You may have to give these plants extra waterings by hand until the roots grow into the surrounding soil. For best growth, keep even established plantings moist, and maintain a 2 to 3-inch mulch layer over the soil surface.

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I planted impatiens last summer in beds and pots, and they have grown quite leggy. Can I trim the plants to make them more compact?

If the plants are healthy, trim them. Tall plants might have a foot or more of the top portions removed. The more you remove, the longer it takes the plants to recover. After pruning, give the plants a light feeding and keep the soil moist to regrow the impatiens you remember.

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I have a lion's mane that has been blooming since October, and I would like to prune it back. It has grown tall and is beginning to fall over. However, I see more buds forming. Should I wait until it finishes blooming again?

How badly does it need trimming? It would be a shame to lose the clusters of bright orange blossoms, but if the plant cannot be staked conveniently, you have little choice. With spring growth already beginning, the plant should rebloom quickly.

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I have five poinsettia plants that do not receive enough sunlight. When is the best time to transplant, and how far back should I prune the plants? Do I prune first and then wait to transplant?

Now would be a good time to transplant these sun-starved plants. Go ahead and prune them before the move. Cut them back to within 18 inches of the soil.

Dig the poinsettias by moving around the plants and pushing a shovel straight down into the soil to form the root ball. A ball of soil about 12 to 18 inches in diameter should be adequate. Make sure the soil is moist when you dig. After the ball is formed, dig under the plants and lift them from the ground.

Give your plants a new home in a full-sun to lightly shaded location. Remember to find a spot away from nighttime lights so they can flower naturally for the holiday season. Keep them moist and begin the every-other-month feedings with a general garden fertilizer to encourage growth.

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I have a couple of gloxinias that started to decline after a spring and summer of healthy growth and blooms. I stopped watering and decided to let them "rest." Will they come back?

Gloxinias need a break from growth and flowering. You did the right thing by giving them time off. Most likely you will see growths in a month or two. At that time, you can repot the bulblike portions and resume normal care to produce another round of flowers.

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I have a fairly old spathiphyllum in my home that has been growing in the same spot. Recently, the leaves have been developing brown edges. I water frequently, but this doesn't help. What should I do?

Check the root system. Most likely it has grown pot-bound and cannot take up the needed moisture even though you are applying the water. If the root ball is encased in layers of cream-colored roots, it's time for a new container.

Select a pot that is about 2 inches larger in diameter than the root ball. Gently pry the outer layers of roots apart and repot the plant in a loose potting mix. Keep the soil moist, and your plant should in time sprout growths without the brown edges.

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We received a hyacinth as a gift plant. How many flowers do you get from one bulb, and what should I do with the plant after the bloom is spent?

Usually there is one pretty and fragrant cluster of blossoms. When the flowers fade, the green foliage can last a month or more if you keep the soil moist. The best advice is to toss the plant on the compost pile and keep the pot.

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I recently transplanted some tall, thin petunias to the ground and cut them back. Do you think they will grow more compact plants and flower?

Petunias can remain attractive until mid-June or July, and then they start to decline. Cutting them back was a gamble, but it should payoff with additional blooms before the hot, rainy season destroys the plants.

Some varieties are much more heat tolerant than others, but all seem to succumb to the torrential summer downpours. Keep the plants moist, and feed every three to four weeks with a general garden fertilizer to bring out the blooms.

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I received two beautiful Easter lilies this year and would like to plant them in the garden. Where is the best spot, and what care is needed?

Help your plants rebloom next year by giving them a sunny location , in a sandy site enriched with organic matter. Remove the plants from the container without disturbing the root ball, and set it in the ground with the top of the root ball level with the surface of the soil. Then add a thin layer of mulch.

Keep the lily growing by maintaining a moist soil and feeding lightly once a month with a general garden fertilizer. The leaves and stems should decline by early summer, and the plant can be cut back to the ground.

Mark the spot with a plant tag so you won't disturb the bulb. You can expect new growth around March and flowers by next May.

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Several years ago, I planted impatiens in my back yard among a large cluster of trees. The plants have grown 2 to 3 feet tall and are quite leggy. Can I cut them back? If so, how far down, and when is the best time to do this?

Now is a good time to trim. Plantings can be cut back to within a foot of the ground. Keep the plants moist, and apply a general garden fertilizer monthly to encourage shoots. In six to eight weeks, the plants should be full of leaves and flowers.

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I planted a bed of calla lilies and ti plants in front of my house that receives a half-day of sun and shade. I improved the soil, and I water them regularly. The calla lilies are turning yellow, and the ti plants have brown edges. Why?

Both plants are crying out for water, even though it appears you have provided for all their needs. Lift one of the plants and check the root ball. Most likely it will be dry. Also, the plants are likely pot-bound.

Try resetting the plants by first pulling the outer layer of roots apart. Try not to tear or cut the roots if possible. Then saturate the soil with water at planting so the root balls have to get wet. Keep the soil extra-damp for the next week or two. Direct the water toward the base of the plants again to wet the root balls. This should encourage root growth into the surrounding soil. Then you can begin normal waterings.

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I received an amaryllis that I am trying to keep alive, but it has only one leaf left. What should I do?

Relax, and let your new bulb take a break too. Amaryllis often go through an inactive state at this time of the year and then resume growth during spring. Give your bulb a sunny to shaded location, and keep the soil moist but not overly wet. Also, withhold fertilizer until growth resumes during the warmer weather. Most likely, it will take the plant another year of growth to bloom again.

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I have pentas in my back yard. They are several years old and now are dying. Does anything feed on them? They are getting plenty of water.

Pentas are perennial plants that after a period of a year or two need to be restarted. The decline you observe could be this natural occurrence plus some rot problems encouraged by the heavy summer and early fall rains.

Reduce the waterings to only as needed to keep the soil moist Allow the surface soil to dry, and then give soak the plantings. Use of a 1 to 2-inch mulch layer can help stretch the time between waterings and prevent, overwatering.

Plants that have started to decline will likely be lost. It's best to remove these plants and some of the soil. Add new soil or a potting mix, and incorporate it with the existing site. It may be best to wait until spring to plant new pentas because they often are damaged by winter's cold. Maybe a shorter-lived winter annual would be a good temporary addition.

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I bought a poinsettia for Christmas and would like to keep it in a pot. What should I do to continue to grow it in a container and have it in bloom for the holidays?

It's time to give your poinsettia a larger container. Select a clay or plastic pot that is 2 to 3 inches larger in diameter than what the plant is in now. Use a loose potting soil with good drainage. After repotting, cut 2 to 3 inches off the ends of each stem. Then begin feeding the plants with a 2020-20 or similar product every other week or use a slow-release fertilizer as instructed on the label.

Keep the plant moist and in full sun to light shade. After the poinsettia grows about a foot, cut several inches off each stem. Continue the prunings until the end of August. During the fall, make sure the plant receives no nighttime light, and it should be in bloom for the holidays.

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Our yard lights are on from dusk to dawn. Are these lights affecting the plants in any way?

Most plants won't mind, but if you are counting on fall blooms from poinsettias, chrysanthemums, kalanchoes and holiday cacti, you have to find a way to turn off the nighttime lights.

One option to get blooms for the holidays is to grow these plants in a location that receives no evening light during the fall months. You also could cover them each day at about 5 p.m. during the fall, but this could be a lot of work.

Twenty-four hours of light each day can encourage some plants to produce additional growth and flowers. Often, there is little concern, but with crape myrtles, the extra light might be a problem. The extended days delay their normal rest period, which makes them more susceptible to cold injury during the winter months.

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We bought a nice-looking petunia in a hanging basket about a month ago. Now it has grown lanky and has only a few blooms. Can we cut the plant back and expect it to recover?

Fall has been hotter than normal, and most petunias have that stressed-out look. With the cooler weather ahead, the plants should recover.

Lanky petunias that are still healthy can be cut back to within a few inches of the pot and can be expected to recover within weeks. Place the plants in full sun, keep the soil moist, and add a slow-release fertilizer to the container to feed them for the next few months.

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If a piece of staghorn fern falls from the main plant, can it be saved? I have seen them planted in mulch and soil. What is best?

Sometimes staghorn ferns begin to fall apart with age and lose growing plant portions. Other times, older declining leaves drop or some rot problems develop, and pieces fall to the ground. If the lost plant porions look healthy and have roots attached, they likely can be saved to grow new plants.

One of the quickest ways to give them a new start is in a container of potting soil. Fill the container to within a few inches of the top, and add the staghorn portion. Fill in with soil around the edge of the fallen section, but do not plant it too deep. You might have to give it some support, but the plant should form new roots.

Keep the soil moist, and begin monthly feedings when warmer weather arrives. Your new plant should be ready to add to a basket or a slab of tree fern by next summer.

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Several of the amaryllis bulbs we planted in containers have flowered. Now that the blooms are gone, can we keep them in the containers outside or do they need to be planted in the ground?

It's up to you, but containers are such a convenient way of managing amaryllis in the landscape. When they are in bloom, they can be moved to any area where you would like color. They can be displayed in the home, on the patio or among perennial plantings. Then when the blooms decline,they can be set in a less-obvious location.

Container plantings, need to be kept moist during the growing season, then allowed to dry a little between waterings during fall and winter. They can be fed monthly with a general garden fertilizer or a liquid solution April through September.

The other option is to add the amaryllis bulbs to a sunny or lightly shaded area of the landscape and give the plants normal perennial plant care. Allow the bulbs to remain drier than most perennials during fall and winter; this appears to encourage spring flowering.

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