When injury and damage occur to something you care about, it is natural to want to take action. The hard freezes we have experienced this year have created a lot of brown turf and foliage but let us not act and make things worse with good intentions and poor horticultural practices. This article will summarize the recommendations you will find in the following University of Florida publications available online.
Cold Protection of Ornamental Plants- http://edis.ifas.ufl.edu/mg025
Low Temperature Damage to Turf– http://edis.ifas.ufl.edu/lh067
Ornamental Plants: Don’t prune woody plants that were damaged from the cold yet. Wait until the danger of freezes is past and then determine the severity of the damage. Once the weather warms up, new buds will break along the stems, especially towards the base where they were protected. Another technique to determine if the plant is still alive is to scrape the bark and look for green tissue below. When new growth emerges, remove the damaged wood just above a new bud. Even though some plants like plumbago, bougainvillea and hibiscus may look dead, they typically develop new growth along the stems or from the root system once warm weather returns. Be patient as this may take five to six weeks following spring temperatures. If you can’t handle the brown leaves, perennial plants can be cleaned up a little if they look unsightly but don’t cut these plants all the way back unless you’re willing to give up a security layer for the plant in the event of another freeze.
Palms: More tropical types of palms are at risk if they suffered cold damage. Remove cold-damaged leaves but do not prune leaves if they are still green. As soon as pruning is completed, spray palms with a copper fungicide plus a spreader sticker. Repeat the application 10 days after the first or use a different broad spectrum fungicide. Make sure to cover all the damaged plant material, pruning cuts and center bud with the spray material. Don’t use copper more than twice per year because of potential toxicity problems.
Lawns: Dormant lawns do not require mowing unless you are doing this to trim cool season weeds. Injury to warm-season turf grasses often occurs when temperatures drop below 20°F. In cases of severe freezing temperatures, some grasses may suffer irreversible damage. Cultural factors that tend to promote cold injury include: poor drainage (soil compaction), excessive thatch, reduced lighting, excessive fall nitrogen fertilization (after mid October in the central region ), and a close mowing height.Leave the dead grass in place for now as it will provide protection to lawns in the event of another freeze. Once we are out of danger from freezes, the damaged areas can be lightly raked to remove the brown.
Because cold damage may initially resemble drought stress, people sometimes feel that additional water may be needed. Overall, correct irrigation practices can alleviate many stresses faced by turf, but dormant grass water needs are reduced by about half. A good rule of thumb is to “Skip a Week” during winter months.
Your grass should begin to green up as temperatures and day lengths increase in the spring. At this time, recommended fertility, irrigation, and mowing practices should be resumed for best health of your lawn all season. In mid-February you should begin your weed management program by applying a pre-emergent herbicide (e.g. atrazine for Floratam St. Augustinegrass) to prevent weeds from getting started, but don’t use weed and feed since the lawn cannot use the fertilizer until it begins growing again in Spring. Another pre-emergent option for those trying to kick their lawn’s chemical dependence is Corn Gluten Meal (http://www.turfgrasstrends.com/turfgrasstrends/Herbicide/Use-corn-gluten-meal-as-a-natural-pre-emergent-wee/ArticleStandard/Article/detail/12811). Call your local feed store to check on availability or to have them order it for you.