Back on July 7, 2004, I wrote that “Palms have Panache.” After four years, it’s time to revisit palms and how to care for them.
Plus there are new guidelines from the University of Arizona Arboretum. A truly low care plant, there are a bare five tips to keeping them healthy.
Care tip 1. Leaf it alone! Never prune any fronds ever.
Reason # 1 for not pruning. Palms aren’t “trees.” Palms are upright, tall, semi-woody long-lived, perennial plants. A palm is like a giant onion that lives a long time and gets woody as time passes. For a palm to get properly woody, and strongly so, it needs every frond it grows to turn brown right down to the trunk before being removed.
A palm frond and its attached leaf base is much longer and larger than you expect. The frond includes the outer leaf, the stalk that attaches it to the plant, and the hidden base of the stalk, deep within the trunk. Like an iceberg, you see only about 10 percent of the structure, the rest is hidden. The base of the leaf wraps entirely around the top of the palm, and can extend for several feet down the trunk. The trunk is essentially made of many leaf layers, just like an onion.
The base of the frond is what ultimately turns into trunk — its cells become woody. To become woody, the cells must be alive. That means the leaf must be alive and sending food to the base so it can make the wood that is the trunk of the palm itself. Palms need green fronds to make healthy trunks.
Reason # 2 for not pruning. Palms, being arid-adapted trees, are very thrifty organisms. Under normal conditions, a palm will take all the hard-won chemicals, minerals, proteins and even chloroplasts out of an old leaf and ship them to new growing ones. By cutting off a green leaf, you are robbing the palm of all those resources, forcing it to start over from scratch for the new leaves. This causes undue stress on the palm.
Reason # 3 for not pruning. We live in the desert, where the summer sun is blazing hot. Just as humans need some shade to keep from dehydrating in the blazing rays, so do plants. And they can make their own shade! Those nice brown leaves bend downward and keep the trunk shaded and cool.
Reason # 4 for not pruning. Stressed or damaged palms are more likely to become infested by insects. Particularly deadly is the giant palm-borer. This insect starts on the succulent young leaves and works its way to the sugar-rich heart of the palm, killing it.
Reason # 5 for not pruning. The lovely black and orange orioles fly into the area for the summer, knowing that there will be plenty of monsoon bugs to eat and to feed their babies. They nest in summer and raise lots of little orioles to follow in their bug-eating footsteps. Orioles are weavers and will weave their nests from dried palm fronds. What better place to nest than under the dried palm fronds?! It is cool, shady, and best of all, waterproof in even the worst monsoon downpour.
New Improved Care Tip 1. Since people have it in their heads that dead fronds are unsightly, do what they do at the University of Arizona Arboretum (the entire campus is the Arboretum). Remove only the fronds that are long dead. Trim the tree so the top tuft of green and brown leaves forms a tidy oval or egg shape. Ideally do this pruning in fall, when shade is less needed by the palm, and they are starting their winter dormant phase. The U of A has determined that palms pruned in this manner will not drop older fronds.
Care tip 2. Do not “skin” the palm. Leave old frond stubs on the trunk, they help protect it from insects. Put the power tools away. Do not use a saw to shape the trunks of palms. Let the palms shape themselves. They will do it correctly.
Care tip 3. Never use climbing spurs on palms, they can severely damage the trunk and lead to insect infestation, and possible tree death. Use a ladder or lift.
Care tip 4: Fertilize your trees at least once per year. The best time is during active summer growth. Use a general purpose or lawn-type fertilizer at half strength. Mix with water and pour all around the tree. Next, put a hose down and let it drip overnight. This will soak the soil and carry the fertilizer down to the root zone. Palm roots are often six to eight feet deep.
Care tip 5: If monsoon rains don’t do this, soak the plant deeply three to four times during the summer months to encourage healthy growth that helps fight off giant palm-borers and makes healthy solid trunk for future fronds to hold on to.
That’s it. Five simple steps to healthy, long lived, trouble free palms.