Palms - Do Not Over-Trim

By Paul Craft

The pruning of palms is far simpler than pruning woody ornamentals. Dead leaves and old fruit bracts are all that need to be cut from palms, it is easier still for crownshift palms because the leaves shed immediately when they turn brown. Picking the old leaves up and disposing of them is all there is to do.

It is best to cut leaves only after they have completely turned brown. Palms will translocate nutrients from the older leaves to the newer leaves. By cutting leaves that are still green, the tree is robbed of these nutrients. At times, partially green or yellow leaves can be quite unsightly and it is safe to cut these leaves if they are more than 50 percent brown.

If it is desired to prune a palm, the general recommendation is to trim off only those leaves that hang below the horizontal plane of the crown, leaving a sufficient leaf crown to maintain the health of the palm. Trimming any more can be injurious to the palm in the long term, especially if done on a regular basis. Allow the palm to grow back a complete rounded crown before pruning again. It is also particularly important that a regular fertilizer regimen be followed to guarantee nutrients available to the palm since it is being robbed of nutrients when the leaves are cut.

Leaves should be cut as close to the trunk as possible. The remaining leaf base will eventually fall off, but it may take several years. In some species, such as Phoenix, an interesting pattern can emerge on the trunk by cutting the leaves off at a certain point, adding an ornamental feature to the palm. Trying to strip the leaf bases from the trunk before they are ready to fall off can cause scarring of the trunk.

Equipment used to trim palms should be treated with isopropyl alcohol or hydrogen peroxide before moving from one palm to another. This will help prevent the spread of any disease such as lethal yellowing or fungal diseases.

Untrained tree trimmers partake in a practice called hurricane trimming that is detrimental to the palms. It has gone on so long that many homeowners think it is a practice that does not harm the plant. Palms are very wind-resistant plants, not bothered by high winds nearly as much as woody trees are, yet there is a myth that cutting most of the leaves from a palm will help it survive a hurricane. The opposite is true, severe trimming jobs weaken the crown to the point it can snap off in moderate winds.

If the hurricane cut is done on a yearly basis, the leaves will become smaller and the trunk will become narrower, resulting in what is called pencil pointing. The palm will become weaker and more prone to disease, nutritional problems and breakage if high winds do arise.