Garden Club of Cape Coral | There’s a chill in the air!
We are facing a situation in Southwest Florida that is all too familiar to area gardeners: following hurricanes Helene and Milton in September and October, many of our plants were damaged and either broken or required pruning. The warm temperatures that followed encouraged a burst of new growth. The past two weeks have been unseasonably cool, and that tender new growth will be in danger of being burned by even lower winter temperatures and wind.
Over the past five years, January had the largest number of cold events annually, but cold temperatures also occurred in December, February and November. Based on this pattern, it is wise to educate yourself about cold weather and take some proactive steps to avoid damage to your garden.
Even though we don’t usually confront the freezing temperatures that north and central Florida can experience, many tropical plants suffer “chilling injury” at temperatures below 50°F. If plants have not been “acclimated” by gradual temperature decreases over a period of time, damage is more likely to occur.
How can you recognize cold-damaged plants?
I have recently noted tender plants such as begonias and impatiens, especially those plants in pots, that have suffered chilling injury which makes the plants appear to collapse. Plants can also desiccate or dry out; you might notice brown leaf margins or leaf tip burn, or in severe cases, totally yellow or brown leaves. This desiccation is usually caused by dry winds associated with cold fronts that move into our area from the north, causing water loss from leaves that cannot be replaced by a cold root system.
As you may have noted after Helene and Milton, this damage is not always immediately apparent; many of my plants exhibited wind damage several weeks after these storms when leaves turned brown on the edges and suddenly yellowed and dropped. Palms also suffer from cold damage; chilling injuries can result in damaged fronds and trunks, which can encourage secondary fungi and bacteria damage that can cause decay.
There are fortunately some practical steps that you can take to protect your plants. During cold spells, potted plants should be moved either indoors or onto your enclosed lanai or porch; if you can’t move potted plants on your lanai, you should group them together and bank mulch around the pots to preserve heat. Large ornamental plants that are planted in the ground can be covered; the covers must extend to the ground to trap radiant heat and should be anchored with bricks or rocks.
During a cold snap two years ago at Christmas I used sheets to cover plants, and while they were helpful, landscape cloth (available on Amazon) is significantly lighter and does a much better job. DO NOT use plastic to cover your plants as the plastic will actually transmit cold air to your plants!
A thorough watering before a cold spell is beneficial to plants because it helps retain heat in the soil and provides a ready source of moisture to help desiccated plants once the temperature rises. Running your irrigation system during a cold spell is not recommended since residential irrigation systems are not configured to maintain a film of water on the leaves as commercial irrigation systems do.
What should you do if your landscape suffers cold damage?
Any annuals that have collapsed should be removed from the garden immediately as they will not revive and could promote viral or bacterial growth in their decaying material.
Check the soil around your plants for moisture; once the sun is out and the temperatures are climbing, water can help warm the soil and provide the necessary moisture that even injured plants require. You can remove dead leaves once they turn brown, but you should wait until new growth appears to do any pruning.
You may be tempted to fertilize your plants to assist them in their recovery, however, if you apply fertilizer too early and we have another cold spell, the tender new leaves will be the first to be damaged. It is better to wait until March when the danger of cold weather has likely passed before you add fertilizer to your garden.
Extremes in our weather will always provide a challenge to gardeners, and we need to be prepared to respond to these events. Setbacks in the garden are always discouraging, but thankfully we have the promise of warmer days to look forward to long before our northern friends will experience spring. With good preparation and care after any cold weather events, we are fortunate that our gardens will soon be thriving in our beautiful subtropical climate!
Cathy Dunn is a Lee County Master Gardener volunteer, Garden Club of Cape Coral Member and president of the James E. Hendry Hibiscus Chapter. Visit GardenClubofCapeCoral.com. Like us on our Facebook page.