Q: I have a palm tree that is starting to shed its outer layer. It looks terrible. We were told about 10 years ago not to skin palm trees because of borers. Is this correct?
A: I am not sure which borer was mentioned. Palm trees do not get borers or sunburned trunks that I know of. Borer damage doesn’t happen much probably because it’s a monocot.
Palm trees do not get the typical flatheaded borers (landscape borers) that are common to fruit trees (dicots) and many different landscape plants (also dicots). I am cautious because I used to say that about pine trees and borers as well and I was proved wrong. Pines do occasionally get borers.
About 30 years ago, I skinned a windmill palm to see what would happen. Skinning it (removing the outer fronds with a sharp knife) had no effect on it.
Some palms do get the “giant palm borer” in climates warmer than Las Vegas. We knew so little about this pest in palm trees 30 years ago that we were guessing if the Las Vegas climate was warm enough for this pest to survive. The giant palm borer, a surviving pest here, has been dismissed. It’s surmised that it is too cold in the winter for its survival.
Some palms get carpenter bees that leave holes in the base of their dead fronds that are still attached to the tree.
Skinning palm trees can be expensive. The base of every frond must be severed from the trunk and removed. Plus, palm fibers are very tough and so the knife must be sharpened frequently.
As palms get taller, skinning requires a ladder and time. It is not difficult. To my knowledge, skinning palms does not increase borer activity.
Q: What do you suggest that is a fast-growing tree, looks good and doesn’t require much upkeep?
A: I don’t like these types of questions because my plant selections end up going back and forth. Many people do not like my ideas for plants. I am more comfortable answering questions about specific trees, their merits or shortcomings.
Whenever a plant (every plant uses water) is added to a landscape means that its water use increases. To reduce water use of a landscape requires that the total number of plants is reduced, smaller plants are used, and these plants are selected from desert or dry environments.
I am infamously quoted as saying that a landscape full of plants is an unimaginative one. Anyone can plant a plant.
In the desert, walls can have murals that are repainted every few years, structures can be built out of concrete or metal (gazebos, pergolas or shade structures), artwork can be incorporated into a landscape, mounds of landscape soil makes it more interesting, different sized rock can be used, boulders can be placed, and none of these ideas need water.
Be creative yourself or hire creative people to do the work you specify.
Q: How and when do you cut back ocotillo plants to get them to fill out?
A: I am guessing you want your ocotillo plant to get taller and wider. Like any plant, the only thing missing is time. With time, your plant will get larger.
You can speed up this natural increase in size by judiciously adding fertilizer and water. Fertilize once or twice a year in small amounts. Increase the amount of water you give to an area equal to its spread, but don’t increase how often water is applied.
Q: Why do my pear trees have tips with no leaves? They look like they are dead, and they are black.
A: Dead stems are brittle and will snap when they are bent. Living stems are supple and bend easily. Check to see if your pear tree has supple or brittle small branches by bending them to a right angle. Sometimes naked branches just need time to put on some leaves.
If fireblight is a possibility, then prune these black parts and try to get it to grow back from the base of its stem where buds or new growth are seen. The standard recommendation is to prune it back 12 inches, but it depends on how infected these parts are. Certainly 12 inches is plenty.
Sanitize the pruning blades with alcohol between cuts. Get any possible disease stems out of the area after pruning.
Many plants are a bit squirrelly because of the prolonged spring weather we had. For instance, palo verde plants are blooming now and in Tucson. Someone reported acacia were flowering a couple of weeks earlier than in Las Vegas. However, a desert city in California I visited this weekend — very close to our elevation and climate — also had acacia flowering at the same time as ours.
Q: I read the question you printed about scarring on my cactus pads. I have the same problem. Is there anything I can spray or feed them to prevent this scarring?
A: There is nothing specifically approved for use to prevent or cure scarring in cactuses. The scarring of pads is found in cactuses with flat pads or paddles such as Opuntia, aka nopal, beavertail, bunny ears and other common names that are popular.
The pest that causes this kind of damage can be called either the cactus moth or Opuntia leaf miner. It is a long, winding miner just under the skin, widening as the pest gets bigger.
In severe cases, this pest may tunnel into the pad and even the stem and cause the pad or the plant to die. If left untouched and the climate is OK, this pest can increase in number and spread to your neighbors’ cactuses.
This pest can be found naturally in Central and northern South America and has spread into Texas, New Mexico and southern Arizona. And now it looks like it’s in the warmer parts of Nevada as well.
Not much can be used to control this insect, but you might try soap and water sprays every two or three weeks starting when damage is first seen. These types of sprays protect the plant.
A second approach is curative. A possibility is to spray the plant with imidacloprid (a popular borer control insecticide for fruit trees and landscape plants) starting when damage is first seen.
If the cactus is large and the damaged areas are found only on a few pads, try pruning the damaged areas or the entire pads from the plant and burning the pads or pieces after they are pruned. This would be a natural approach.
Q: Is there a way to transplant a pony palm? I just would like to make a shoot. Can I trim the corner on the inside and will that make a shoot?
A: The common name is the ponytail palm. It is a semidesert plant, but it is not a palm at all.
True palms are monocots. Most of our landscape plants, including the ponytail palm, are dicots. It is closer to an agave (also a dicot) biologically speaking than a palm tree. It’s just that it looks like a palm, so we call it a palm. Think cycad, aka sago palm, but it is really a dicot as well.
The shoots or suckers are produced at the base of its swollen trunk. Sometimes these suckers can be removed and, under ideal conditions (get them when they are small, propagate them with a little bit of light and use rooting powder), they will root and become small transplants. The swollen trunk is thought to be used for storing water.
This plant is native to the drier parts of Mexico so winter cold can sometimes be a problem if it’s planted outside. It is usually grown as an interior plant but can be grown outside in warm desert or semidesert climates.
Plant it on the east side of a home and at least 5 feet from a hot wall. Make sure it has good drainage.
Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.