Freeze damage on a queen palm. (Photo by Allen Owings)
Windmill palm on the LSU campus in Baton Rouge. (Photo by Tom Pope)
News Release Distributed 02/14/14
By LSU AgCenter horticulturist
HAMMOND, La. – Palm trees have become increasingly popular in Louisiana home landscapes recently, and this resurgence mainly can be attributed to the lack of severely cold weather over the past 30 years.
Some of us remember the winters of the early 1980s and late 1980s that resulted in considerable damage to palms around the state. More recently, the winter of 2010 damaged palms with several nights in the upper teens in south Louisiana. And now, this year’s significant cold weather has done it again around the state.
With temperatures in the lower teens on several occasions in north Louisiana and even the upper and mid-teens in some locations in south Louisiana, palms have been damaged, and a good numbered have been killed.
The species of palms you have in the landscape, the locations where they are planted and their condition before cold weather set it will determine how much your palms may have been damaged. Queen, sabal, Canary Island, Sylvester, Mediterranean fan and cabbage palms, along with some other species, are showing cold damage. Even more cold-hardy palms, such as windmills, have damage. Also, you can see considerable brown foliage on sago palms, which is not a palm but a member of the cycad family.
Palms have a central growing point (bud or heart) at the top of the plant where the fronds emerge. This growing area is exposed to weather conditions. People typically wrap a palm trunk in burlap or frost-protection blanket to prevent cold damage, but this does no good. The growing point where fronds originate is the area that must be protected from cold weather.
Fronds on even some of the more cold-tolerant palms have been damaged by this winter’s cold weather. So, what should you do?
If a portion of a frond is still green, leave it on the plant. Be sure to keep the fronds on the plant as long as possible. It takes palms a considerable amount of time to produce new foliage after old foliage is damaged.
We need to be extremely patient with damaged palms. Palms usually start their season’s growth long after other shrubs and trees start their spring growth flushes. A sign that a palm is dead is when the spear leaf in the center of a palm canopy can be pulled out of the bud or heart. If palms do start regrowth by early summer, it is possible that the new, emerging fronds will be misshapen.
Even though they suffered some damage, one of the most cold-hardy palms you can plant in Louisiana is the windmill palm. This species can be grown across the state and is one that can be planted in more northern locations.
Windmill palms are cold-hardy to 15 to 20 degrees and can tolerate lower temperatures for short times. Windmill palms are not considered as “sexy” as some of the newer species being used, but their durability should be given high consideration when selecting landscape palms for Louisiana.
Windmill palms have average heights of 15 to 25 feet but can be as tall as 40 feet. Trunks are slender, and mats of dark brown, hair-like fibers coat the trunk on younger palms. Windmill palms like ample water but don’t do well in extremely moist soils or standing water. Low, poorly drained areas will significantly slow growth of windmill palms. They have high drought tolerance and moderate salt tolerance.
If you want to replace cold-damaged palms this year, plan to plant in early summer. Ideally, palms should be planted at the hotter times of the year. Root growth on palms is different than other landscape plants. Root growth in Louisiana is best in June, July and August – times of the year when many other plants are not growing new roots. Palms also benefit from annual fertilization in early summer.
You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on . You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.