Landscape

How to protect plants against the cold

When Winter Weather Strikes

t’s not a stretch to call Southwest Florida a tropical paradise. Palm trees are everywhere. Flowers bloom all year. Winter is a misnomer; it never really gets cold here. Well, almost never. When it does get cold, though, there is a real threat to some types of plants, and that’s when green- thumbed Floridians take action to make sure that their cherished greenery survives the occasional cold spell.

According to Robert Van Winkle, chief meteorologist for local television station NBC- 2, “Cold weather threatening plants in this area usually happens at least once or twice every winter. Some years we have several “threatening” mornings; other winter seasons can be uneventful.” KNOW YOUR REGION What brings the cold weather? Van Winkle points out that “we need a ‘ push’ from upper- level winds to transport cold air from the North down this way.” An unusually large dip in the jet stream provides such a push. According to Van Winkle, the worst cases often involve “clear skies, light winds, and low dew points.” It is these conditions that allow the heat from the earth to radiate out into space, thus dropping temperatures rapidly after sunset.

Even when the cold air moves in, there is often a wide variation in low temperatures in the region. “Inland areas are usually more threatened with frost and freezing weather than coastal areas,” Van Winkle notes. “The warm waters have a moderating effect on temperatures near the coast and especially for the islands.”

Cold air is denser and tends to sink into lower lying regions. These are the so- called “frost pockets” that typically occur in valleys or other lowlands. This effect is most

WITH PROPER PREPARATION, YOUR FAVORITE

PLANTS WILL STILL BE AROUND LONG AFTER YOUR NORTHERN FRIENDS GET DONE LAUGHING AT OUR FLORIDA- STYLE “WINTERS.”

pronounced on calm nights.

Highly developed areas, such as the cities, tend to be warmer. The heat of the day is often trapped by building materials such as concrete and asphalt. This heat is given off at night, keeping temperatures up in what is called the “urban heat island.” PREPARE The National Weather Service provides official cold/ frost warnings when necessary. If damaging cold is predicted, first determine what you really want, or need, to save. Brown flowers or leaves may look bad, but they will drop off and grow back. Most healthy perennials will survive, even if everything above the ground dies, as long as the roots are protected.

If the plants that you want to protect are small and in containers, simply bring them inside. Any type of structure will work, and it doesn’t have to be heated. Plants in con- tainers are actually at greater risk outside since the roots are more exposed to the cold; the sides of the containers will radiate heat. If you must leave them outside, push the containers together and cover their soil with mulch.

If the plants must stay outside, you can also completely cover them. The ground always has some warmth in it. Covering a plant will keep that warmth from radiating out into space. It works like a blanket. Any type of cover will help— blankets, sheets, table cloths, or even putting a trash can over a plant. Cover the plants as soon as the temperature begins to drop. This will keep in as much heat as possible. Avoid using plastic. Frost cloths, or polyester fabric sheets, can be purchased at many gardening outlets. It is best to actually make a tent over the plants. Avoid having the fabric touch the leaves of the plants, since the cold can be transferred to the leaf.

Mulching is a great way to protect the plant’s roots from the cold. It has other advantages, too, such as reducing the soil’s water loss and reducing weeds.

Watering your plants before a cold

night can also help. Wet soil will cool more slowly. Farmers will sometimes use sprinklers all night to protect valuable crops. This can be tricky to do and may even damage plants if done improperly, so leave this technique to the professionals.

Finally, after the cold has passed, don’t rush out to prune dead foliage. The plant will respond to this by sending out new growth. This new growth is even more susceptible to damage if another cold spell occurs. PLAN AHEAD There are also steps that you can take well ahead of time to avoid cold or frost damage to your plants. Debbie Hughes, senior horticulturalist at the Edison & Ford Winter Estates in Fort Myers, gives these tips: “First, pick plants that work for our area. There were plants that Mr. Edison tried that didn’t seem to like the occasional cold. Second, keep plants healthy. A healthy plant can withstand more stress. Fertilize appropriately. Third, don’t encourage [ cold- susceptible] new growth in the winter by trimming unnecessarily. Avoid pruning in the fall.”

It’s not hard to protect your plants from Florida’s occasional cold spells. With proper preparation, your favorite plants will still be around long after your Northern friends get done laughing at our Floridastyle “winters.” Freelance writer Ed Brotak is a retired meteorology professor turned stay- athome dad. He and his family live in western North Carolina, but they love Florida and vacation here every chance they get.