Severe pruning can lead to sunburn
Q: I bought a home with a beautiful mature palo verde tree in the front yard. When I moved in, it was severely trimmed with one of the branches “scabbing.” I found no drill holes from insects. I wondered if this branch was sunburned as these trees have no bark. What do I do?
A: There’s not much to do now. From the sound of it, the tree was pruned severely which opens the canopy to damage by intense sunlight. For me, a good pruning job is when I can look at a tree and wonder if it was pruned at all.
Wait and see what happens. In the meantime, irrigate with extra water under the canopy of the tree to get it to fill out quickly and cast some shade on the inner limbs. Spreading a high nitrogen fertilizer like 21-0-0 on the soil surface directly below the canopy just before an irrigation helps to produce new leaves and stems and increase shading.
Desert trees like palo verde grow leaves and shoots rapidly when water is available and don’t grow very much when water is not. The application of a high nitrogen fertilizer encourages this growth.
No reason to alter the irrigation to this tree permanently. Spread the fertilizer under the canopy and put a hose with an inexpensive sprinkler that throws water in a 6-foot-wide circle there. Water this way every two or three weeks starting now in addition to the water it’s already getting. The tree will respond with a flush of new growth in about a week to 10 days.
The tree will naturally produce new growth in response to those excessive pruning cuts. The tree responds to pruning cuts regardless of what we do, but extra water and fertilizer make everything happen more quickly.
Q: While trimming my Mediterranean palm I discovered scaly stuff on the new growth that looks like fuzz. I was worried about diseases. None of the other Mediterranean palm trees look like this. I sanitized my tools until I hear from you.
A: Don’t worry about it if the tree otherwise looks healthy. Thanks for sanitizing your tools. Diseases are easily transferred from one plant to another when cutting into wet and succulent new growth. Expect the same care from people who prune plants for a living as you would when visiting the doctor’ s office.
This fuzziness on new growth is called indumentum, literally meaning garment or clothing. No one knows exactly why some plants like rhododendron produce a lot of fuzz on new growth while others don’t. The amount of fuzz can be variable because palms interbreed a lot (hybridize), and new plants are started easily from hybridized seed.
Q: We found bees burrowed into the trunk of a pine tree as well as flying all around it. I am concerned since we have small children. What’s the best way to get rid of these bees and possibly save the tree?
A: Wild bees can pose a physical threat to people and other animals if they aren’t managed. If the bees are not going to be managed properly then eliminate them.
Probably the easiest way to exterminate them is to spray where they live thoroughly with soap and water, rather than an insecticide, during the early evening hours when they’ve come home. Use any liquid dish detergent at the rate of about 1 tablespoon per gallon of water. Thoroughly soak their living area when most of the sunlight has disappeared.
It is thought by entomologists that soapy water more easily enters air passageways and causes them to suffocate. This is the reason why soap and water is an effective insecticide that targets all insects. Selection between controlling good guys and bad guys is the responsibility of the applicator.
Q: We replaced a new bottle tree where an old one was growing. I didn’t have the heart to throw out the old one, so we moved it. It hasn’t done well in its new location for the past three years; there are still a lot of limbs dying and leaves yellowing. Can this tree recover or not?
A: Moving a tree to a new location is not an easy job. It’s difficult for me to give you an answer because I know so little about how it was moved. But here are some key issues to consider when moving trees and expecting them to live. In your case, removal or not depends on how long you can tolerate the ugliness.
Let’s cover some key points that improve the success of moving an established tree to a new location and maybe help you decide one way or another.
Time of year. Move it as early in the spring or early in the fall as possible. Newly established trees need cool weather when first getting established. Early summer months and during the summer are probably the worst times of year for trees and shrubs to get established. If I had my druthers, I would pick the fall months.
Age of the tree. Trees planted in the ground for a couple years are easier to move than trees growing in the same spot for a decade. This is for several reasons but primarily due to the loss of roots.
Remove one-third of the canopy. To compensate for the loss of roots during the move, reduce the canopy by one third before the tree is moved. Two or three large limbs removed from the canopy is usually enough.
Improve the soil. Make sure the soil in the new location drains water in eight hours or less and mix soil amendments and phosphorus fertilizer 12 to 18 inches deep.
Stake the tree. Make sure the roots of the tree do not move during the first couple years after relocation. If relocation was easy, maybe staking will take only one year. But if the tree struggles after a move, expect to stake it for two or three years.
Expect transplant shock. Transplant shock is the time a tree needs to recover after planting or transplanting. The length of time varies with the condition of the tree and how carefully it was moved.
Will it ever get established in its new location? Maybe, but it may look bad for a while depending on how much you deviated from good transplanting practices. If it does get established and you see new strong growth again, prune it to remove dead wood, shape it and encourage strong natural growth.
The leaves are yellow because the roots were damaged. This will disappear as tree roots recover but the addition of amendments for correcting iron chlorosis will help.
Q: I have nectarine, fig and peach trees all with problems. The nectarine is producing heavily scarred fruit that never develops, the fig tree drops its fruit before it’s ready and the peach tree produces small fruit that never matures. Could wind be a problem on these trees or the late spring frost?
A: Except for the scarring of the nectarine fruit, this all sounds like a lack of water. Did you know that trees can suffer from a lack of water even if they are watered every day? It’s true.
The amount of water that trees need is a set amount. If the tree must have 10 gallons of water each week to survive and you water it with only 1 gallon daily, the tree will suffer from a lack of water even though it is watered daily.
Each time the tree is watered, make sure the water wets the soil 18 inches deep after the irrigation has finished. Let this tree drink from this applied water and water it again when half of it is gone. Applying wood chips to the surface of the soil extends watering about one extra day during the summer months.
The scarring of nectarine fruit is due to Western flower thrips. Rotational sprays that include Spinosad help control thrips if started as soon as fruits develop in early spring.
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.