By Dan Gill

LSU AgCenter Horticulturist

(05/13/16) Winters have been relatively mild in Louisiana over the past few years, and I see lots of palms being planted around the state. They add a wonderful tropical look to the landscape and are popular around pools. When choosing palms, however, hardiness is a major concern, particularly in north Louisiana.

How they grow

A palm is a woody plant, but the internal structure of the trunk is different from typical trees and looks more fibrous. This structure is quite strong and helps palms stand up to high winds. It is also the reason the trunks of palms, unlike those of most trees, do not increase in diameter with age, giving the trunk a unique columnar appearance.

Another unique characteristic of palms is that they do not branch. A single growing point produces the trunk and the foliage. If this place of growth should be killed (by a freeze, for instance), the palm cannot regenerate a new one, and it dies. Never cut a palm back to try to control its height because it will die.

The leaves of palms are called fronds, and these are usually large and dramatic. Palms have two basic forms of leaves – pinnate or feather-shaped fronds, and palmate or fan-shaped fronds. With most palm species, the leaves form a crown at the top of the trunk.

Selecting palms

A number of considerations go into deciding which type of palm to plant. The shape and color of the fronds, the mature height and width, overall appearance and light preferences of the tree will need to be considered.

Most palms are native to tropical, frost-free climates, and we must choose carefully to make sure the palms we plant will be hardy here. Although Louisiana has relatively mild winters, particularly south Louisiana, freezing temperatures are possible. For this reason, you should always find out how cold hardy a palm is before making a final selection. Ideally, palms planted in south Louisiana should be hardy down to 20 degrees and in north Louisiana to 15 degrees.

Palms come in a wide variety of sizes and shapes. The classic palm shape is a single trunk topped with a head of fronds. But palms that grow this way vary tremendously in height and spread, and this must be considered in selection. Some palms grow in a more shrub-like fashion, such as the dwarf palmetto, saw palmetto and needle palm (which is hardy to below zero if you are looking for a very hardy palm).

Most palms prefer a full sun to part sun situation, but a few tolerate or prefer some shade, including the Chinese fan palm, lady palm and bamboo palm. This is another factor that should be considered when selecting a palm for a particular spot in your landscape.

Purchasing and planting

Palms are relatively expensive. Generally they are grown from seeds, and it takes a considerable amount of time to produce a salable plant. The more time in production, the more a grower has invested in the plant and the more you will pay for it.

Palms may be purchased grown in containers or grown in the ground and dug for planting – balled-and-burlapped.

When planting palms, dig the hole two to three times as wide as the root ball and just deep enough to accommodate it. Thoroughly pulverize the soil you remove from the hole. If container-grown, remove the palm from the pot and place it into the hole. If balled-and-burlapped, place the palm in the hole with the burlap in place.

Once the tree is in the hole, remove any nails, twine or wire and then fold down or remove the burlap. Next, fill the hole halfway with the thoroughly pulverized soil that was removed to make the hole, settling the soil by pushing a shovel blade into the soil all around the root ball. Finish filling the hole and add water to finish settling the soil. Apply a mulch to help conserve soil moisture and prevent weeds.

Bracing may be necessary for taller balled-and-burlapped palms to help stabilize them until their root systems grow back; however, the braces should never be nailed directly into the trunk. (Remember, palms do not have the ability to heal wounds.) An insulated collar made of wood or metal can be used to support the trunk, or rope can secure the plant into place. The supports can be removed after about eight months.

Hardier palms for south Louisiana include:

– Blue hesper (Brahea armata)

– Bamboo palm (Chamaedorea microspadix)

– Canary Island date palm (Phoenix canariensis)

– Needle palm (Rhapidophyllum hystrix)

– Texas palmetto (Sabal mexicana)

– Dwarf palmetto (Sabal minor)

– Cabbage palm (Sabal palmetto)

– Saw palmetto (Serenoa repens)

– Windmill palm (Trachycarpus fortunei)

– Pindo palm (Butia capitata)

– Mediterranean fan palm (Chamaerops humilis)

– Chinese fan palm (Livistona chinensis)

– Lady palm (Rhapis excelsa)

– Queen palm (Syagrus romanzoffiana)

– Petticoat palm (Washingtonia filifera)

– Washington palm (Washingtonia robusta)

Hardier palms for north Louisiana include:

– Needle palm (Rhapidophyllum hystrix)

– Texas palmetto (Sabal mexicana)

– Dwarf palmetto (Sabal minor)

– Cabbage palm (Sabal palmetto)

– Saw palmetto (Serenoa repens)

– Windmill palm (Trachycarpus fortunei)

Chinese fan palm (Livistona chinensis) Photo by Tom Pope

Chinese fan palm tree form (Livistona chinensis) Photo by Tom Pope

Pindo palm (Butia capitata) Photo by Tom Pope

Cabbage palm (Sabal palmetto) Photo by Tom Pope