- Do not act in haste with your pruning and cleanup. Completely dead material can be removed, especially if the stems of the shrubs have frozen and split. But if you’re not sure how to tell or have any doubt, leave things be for a while. Burned foliage on live stems will start to wither and fall of its own accord, and when the plants put on new growth this spring, you’ll be able to easily tell what’s dead and needs to be removed, and what’s recovering. Prune broken limbs which may have cracked under ice and snow loads, the tops of burned ornamental grasses, palm leaves which are completely (not partially) burned, and you can clean up your perennials now. You can also prune mushy prickly pear and agave leaves to remove them as those leaves won’t recover. Not all agave were seriously damaged – some types are very cold hardy! Agave showing damage will often pup up around the base of the frozen plant to regrow, so don’t pull plants from the ground at this time.
- Completely dormant, deciduous plants are probably just fine. We’ve been asked about shade trees and shrubs which were dormant if they need any care, with fruit trees and Japanese maples being the most frequent questions. Those plants won’t be a problem.
- Roses – It’s time to prune roses back anyway. Go right ahead! Prune them normally.
- Palms would benefit from an application of fungicide. The growth points of palms are at their tops, where the foliage sprouts from their crowns. If this growth point is damaged by the cold, the plant could die. An application of fungicide (we use ferti-lome Systemic Fungicide) will help palms with minor freeze damage to the growth point recover by slowing decay. Wrapping palms before a cold snap as severe as this past week is best, but whether you wrapped the palms or not, fungicide solution slowly poured into the palm’s crown is the only thing you can do at this point which can help. Again, please wrap palms prior to severe cold weather in the future – wrap frost cloth around the trunk, up and over the tied-up foliage, and secure the flap over the top to protect the palm’s vulnerable growth point.
The plants we’ve seen with the worst damage in this freeze were palms, ligustrum, pittosporum, gardenias, loropetalum, and certain varieties of abelia. But they aren’t the only plants with damage – many commonly used shrubs have a small amount of damage from the freeze, particularly on their newer growth. The most important thing at this point is to be patient. Most plants will recover, given time to do so.
Burton specializes in diagnosing and solving plant problems. If you have a question for Burton, please email him at firstname.lastname@example.org and include photos showing the problem.