After The Freeze

 

Will plants recover faster by watering?

Extra water won't help plants heal cold-damaged leaves and stems. This tissue is most likely dead and not capable of using watering.

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The lawn has turned brown. Will it recover faster if I mow it closely?

Let the brown leaf blades remain and skip the close mowing. The dead blades can provide insulation from future cold for healthy rhizomes growing close to the ground. Besides the brown appearance, lawns do not seem to be severely damaged by the cold. Most should recover when the warmer weather returns. The growing green grass will hide the brown in time. If you can't wait for the complete recovery, a good raking as the lawn begins growth can remove the dead blades.

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Our plants are damaged but appear to have survived the cold. Should I apply fertilizer now to encourage new growth?

Winter is not over yet, and more cold may be on the way. A quick application of fertilizer now may stimulate growth that could be damaged by cold later in the season. Wait until the normal feeding time which for most trees, shrubs, and vines is mid to late February. Wait to feed the lawn until late February or early March.

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I have noticed the cold did me a favor and killed the crabgrass in my lawn. Will this be enough to keep the weed out permanently?

Regretfully the cold is not a permanent cure for crabgrass. At first all the stems may appear dead, but some usually survive to restart the infestation. Do your lawn a favor and remove as much of the dead and live crabgrass at this time. There are lots of crabgrass seeds ready for the spring growth in previously infested lawns. When the weather warms, till the ground and fill in bare areas with sod to cover the seeds. Also apply a crabgrass preventer during mid-February to prevent seed germination. A repeat application is needed in about 60 to 90 days, following label instructions, to keep the lawn free of crabgrass.

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It got quite cold at my house. Did the freezing weather help control the insects in the landscape?

You can probably relax for a month or two, but most pests survived the freeze. They huddled among the foliage and developing buds and were not affected by the cold. You may even have brought a few insects and mites indoors with plants to be protected from the cold. When these plants are returned outdoors, the insects keep on multiplying.

Just a few insects including the Caribbean and papaya fruit flies likely saw a significant drop in population. The life cycles of other mites and insects including aphids, whiteflies, scales and chinch bugs slow down during the cold, but are expected to resume activity when warm weather returns.

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Many of my plants are brown. How do I know when they are dead, and should be removed?

Brown leaves are just a hint of the damage that may have resulted from the cold. Wait a few weeks or more before making any decisions. As the weather warms up, plant portions often continue to decline. You may notice stems cracking and bark peeling away as further indication of the cold damage.

In about a month the extent of the cold damage can be detected. Use a knife to scrape along the stems until you find green tissue. This is normally the point where the plant can begin new growth. For some, the green stems may be found only at the ground. Given time, even these plants can recover rapidly because of the well-established root systems.

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Will bringing my foliage plants indoors help them recover from the cold damage?

Damaged leave and stems will continue to decline indoors. These portions should be removed until the die-back stops. The bright light and warmer temperatures inside the home will encourage new growth faster than if the plants were left out in the cold. Also if you plan to continue the good care indoors, fertilizer can be applied as the new growths begin to help speed up recovery.

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Our sprinkler system went on during the freezing temperatures. Most of the plants were coated with ice, and are turning brown. Did the water harm the plants?

Water can be used for cold protection only if it is applied in a sufficient quantity and uniformly during the entire time of the freeze. When a sprinkler system comes on during the freeze and turns off before the freeze is over, damage can often be severe.

The wet plants are super-cooled and temperatures drop well below the air temperature, causing stems and leaves - that would normally not be affected - to freeze. Expect to do lots of pruning to remove damaged portions. Some plants would have survived may have been lost.

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We have lots of citrus left on our trees. How can we tell if the fruit is still good to eat?

Luckily temperatures stayed above fruit-damaging levels in most local residential areas. The fruits usually remain damage free until temperatures drop between 26 and 28°F for 1 to 2 hours. The rule is if the fruit picked from the tree looks good, smells good, and tastes good, it is edible.

Gardeners can detect damaged fruit by cutting them open and examining the membranes between the sections. If white spots appear, they likely were frozen, and should be used as soon as possible.

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I lost most of my flowers. When can I begin replanting?

If you pick the hardy types, you can begin replanting immediately. Pansies and Johnny-jump-ups were not affected by the cold and are almost freeze-proof. Other good cold-weather survivors worth the risk include delphinium, dianthus, dusty miller, ornamental cabbage and kale, petunias, shasta daisies and snapdragons.

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It's been cold all week, so I left the covers on the plants. When should they be removed?

Gardeners can leave sheets, blankets, and similar coverings over the plants as long as the temperatures are dipping to freezing at night and are rising to no more than the 50s during the day. If plastic covers are being used, remove them when temperatures rise above freezing to prevent the sun from burning the foliage. When night-time temperatures are consistently above freezing, remove all covers.

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I brought plants inside during the cold weather. How soon should they be moved back outdoors?

When the temperature returns to normal. If they stay indoors too long, the leaves may drop. Some pests, including roaches, ants and lizards, may move from the plants into the home if they remain inside without debugging.

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Our spathiphyllum was left outside during the cold. the leaves have all turned brown. Is there a chance the plant could survive?

Many plants have lost their tops, but buds near the ground could sprout new growths when warm weather arrives. Part the brown foliage and stems of the spathiphyllum, also called peace lily, to see if there is any green near the soil line. If the plant appears to be alive, you can expect new shoots to develop. Do keep the plant in a warm location to prevent further damage.

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Due to the recent freeze damage, our crotons had to be cut back to the ground. Will the plants still produce new growth, or should they be dug out and new ones planted?

Scratch the stems just below the ground. If they are green, you can expect some growth from the buds insulated from the cold damage by the soil. This growth could be slow in developing, as the buds are often immature. A wait of six to eight weeks after warm weather returns is common.

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I lost my cauliflower and beets during the freeze. Do I have time to start seeds and produce a crop before the weather becomes too warm for these cool season vegetables?

Plant the seeds immediately to harvest cauliflower and beets by April. Gardeners can continue to plant these and other cool-season crops including carrot, cabbage, broccoli, and radish until the end of February. Where available, transplants can be used to replant the garden and reduce production time by 2 to 3 weeks.

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Frost has damaged the ends of our hibiscus branches in one area of the landscape. When can we prune the plants? Why weren't plants in other areas affected?

Some areas of the landscape are always colder than others. Your damaged plants may be more exposed to the wind, or they may be growing in an open area where frosts form first. Perhaps the unaffected plants are near a building or under trees where they are protected from the cold.

Because more cold weather is predicted, don't rush to cut back the damaged hibiscus portions. The brown leaves may insulate the plant from future frosts and freezes. A good rule to follow is when you can't stand the brown foliage any longer, it's time to prune.

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After a recent frost, the weeds turned brown and we can easily see where the patches are growing. Would this be a good time to treat the weedy areas with herbicides?

Make a mental note where the weeds are growing, but delay the herbicide treatments until warmer weather comes and new growth begins. Most lawn herbicides must have green-growing weeds to be effective. The brown weeds can be hand dug from the lawn and the areas re sodded.

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When can I start pruning freeze-damaged trees and shrubs?

Don't prune anything now. Wait to prune cold-damaged oleanders and other tropical shrubs such as hibiscus and crotons after they begin to sprout new growth with the onset of warm weather, maybe by late February. The damaged leaves help to insulate damaged plants from frost and further injury.

Once plants begin to sprout, be sure to prune below them so you cut in to green healthy wood. The cold acts as natural pruning to overgrown shrubs. Several light trimmings through the spring and summer growing season will promote dense growth. New sprouts will form just behind the pruning cut, so if you want the shrub to branch down low, you need to cut some of the stems down low.

Azaleas and camellias should not be pruned until after they bloom. Several light trims to shape wild branches should be all that is needed.

Crape myrtles are deciduous trees, meaning that they lose their leaves during winter. If you trim them too early, they sprout out tender shoots that are likely to be killed by frost or freezing temperatures. Wait until the end of January before they begin to leaf out naturally, but only trim branches smaller than your finger. It is not advisable to follow the common but incorrect practice of hacking into 2" to 6" limbs. It leaves large wounds, which are slow to heal and the resulting branches are weakly attached and likely to break off in the wind.

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I know we are going to be getting colder weather in a month or two. What plants should I cover to protect them from frost?

Locating the cold-sensitive plants in your landscape may take a little work on your part. First identify the plants and then check out their cold hardiness zones in gardening books. Much of Central Florida is in Zone 9. Plants listed as growing in this portion of the state can usually tolerate frosts and freezes with minimal damage. Also, if a plant is listed as tropical, it is probably going to have difficulty surviving the winter without some protection.

Covering the plants can help trap heat in the air and warmth from the soil. A cloth or similar insulating covering is best and should extend to the ground. When the weather turns cold, some form of warmth such as light bulbs can be used to provide additional heat. Make sure the lights are approved for outdoor use and prevent them from touching the cover.

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If I wet down my plants before a freeze, will this protect them?

No. Merely wetting down the foliage so that ice forms on the plant could be more damaging than doing nothing. Ornamental plants can be protected during a freeze by continually sprinkling the plants with water. Sprinkling must begin when the temperatures drop to 32ºF and must continue until the temperatures rise above 32ºF. Sprinkling must be such that the water is evenly distributed and ample enough to maintain a film of liquid water on all of the foliage surfaces.

This practice is impractical and not recommended for homeowners since home irrigation systems are inadequate for such extensive water delivery. Water pressure may drop if several homeowners in the same area turn on their systems, making adequate water delivery impossible. Several hours of irrigation may be necessary and this can cause soil saturation resulting in root rot. It also wastes large quantities of water.

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I planted a desert rose and recently the leaves dropped and some of the stems turned brown. Has it been damaged by cold, and will it recover during the warmer weather?

The desert rose is cold sensitive. It stops flowering and drops its leaves below 50°F. Frosts and freezing temperatures cause the stems to decline as you have noted.

The low temperatures experienced this winter in most Central Florida locations have caused only smaller stems to decline. Prune the brown shoots back into the remaining green portions. Dig and repot the plant and move it to a warm location. With good care, it should recover.

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I have a Miami gardenia. Should it be covered when frost is predicted? It is about 3 to 4 feet tall, and I would hate to lose it.

Most Likely, the variety you are protecting from the cold is Miami Supreme, a longtime favorite with dark green foliage and large 4 to 6 inch blossoms during spring. All gardenias are somewhat hardy and can usually survive a frost with no damage, but they might be affected by a freeze. It's probably best to cover these shrubs, when the temperature gets below 30°F.

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We added an angel's trumpet to our landscape last spring that is now higher than the fence. It appears to be tropical. What should I do about cold protection?

Your observations are correct; the angel's trumpet won't like frosts or freezing weather. The size of mature in-ground plantings make them difficult to protect. A quick covering with sheets tossed over the limbs when a frost is expected might give some protection, but it won't prevent freeze damage.

Most likely you would have to create a tentlike covering over the plant to the ground and add heat to guard against temperatures dipping much below freezing. This is usually too much of a chore for most gardeners to undertake for one plant.

The good news is even if a plant freezes, it usually recovers from buds near the ground to regrow as a shrub or tree when spring weather returns.

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We have a wooden fence in our yard and would like to plant a row of double red hibiscus along the front. Is it safe to plant them during the cooler weather?

Your landscaping idea sounds great, but planting hibiscus during the winter months is always a gamble. If the temperatures dip to freezing, at least portions of the plants are going to be damaged. During a severe freeze, entire plants could be lost.

Buy your plants in the fall if you can get a good deal and keep them in the pots so they can be protected from the winter cold as needed. It's best to delay the inground plantings until mid-March.

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I saw a variegated dwarf schefflera being used in a landscape. Will it withstand our cold weather?

If you are a gambler, you might be willing to take the risk that the winter will be mild and the dwarf Hawaiian scheffleras will survive. Adding tropical foliage plants to the landscape has become popular, but all are sensitive to temperatures of 32°F and below.

Many of the tropicals survive the winter if grown under trees or in protected areas of the landscape where the temperatures often remain a little warmer. Some develop leaf spots because of the cold, but they outgrow the damage as new shoots emerge during spring. Perhaps the best solution is to wait until March to plant the scheffleras and enjoy them for at least most of a year in the landscape.

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We have several purple-leaf sweet potatoes in hanging baskets on our fence. Will they be damaged by cold?

Sweet potatoes continue growth during the warmer fall and winter weather. As the temperatures get cooler the growth slows. During frosts and freezing weather, the foliage is damaged and plants are often killed to the ground. Underground sweet potato root portions survive to sprout new shoots for the spring.

To protect your plants, move them to a warmer location during frosts and freezes. Keep them moist and in a high light location until they can be moved back to the permanent site.

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