New trees need lots of water
Q: Recently we had our yard relandscaped with what was called desert landscaping. We had four privet and two flowering plum trees installed. We noticed about two weeks later that the tree leaves had signs of something eating them. Tiny red ants were running up and down the trees.
We went to the nursery for advice and they said it looked like heat and wind damage. They suggested we create a well at the bases of the trees as they may not be getting enough deep watering. Our water bill has gone from $9 to 25 dollars a month. They also recommended a systemic insect killer that we used and the trees seem to be doing a little better.
We received a note from another gardener saying we should remove the rocks from around the trees. Do you think if we moved the rocks from around the trees and put mulch around them that it might work? We look forward to any help you can provide.
A: You have several issues here and I will address them in the order of importance.
Water: I assume the new landscape is irrigated with drip emitters. Your nurseryman is correct about the heat and wind. In my opinion, it is difficult to provide enough water to establish plants on drippers. I think that drip is best for fully established plants. Supplemental irrigation will aid in getting these plants firmly rooted. You must keep the root ball moist to sustain the plants, and that may be difficult considering the recent high temperatures and wind.
I do not think you need to move all the rocks; simply create a small well. Test soil moisture by using a meter (available at the nursery) or use a screwdriver to see if the root ball is moist. If dry, place the hose near the root ball and let it trickle, thoroughly wetting the root ball. Maintain the schedule you have on the controller as well. This will ensure that the landscape is getting sufficient water. Next year the plants will be in better shape to be deal with the heat.
Actually, $25 is not a terribly high water bill for a good-sized landscape.
Plant selection: Privets and plums are not drought-tolerant plants. They will require considerably more water than desert-adapted trees, but they should survive if properly irrigated.
Insects: From the photos and leaves provided, there is no evidence of insect damage. The small holes in the plum leaves are due to drying out, and the discoloration on the privets is leaf scorch.
I would not be too concerned about the ants as they may be going after the honeydew (sweet excrement from aphids or other sucking insects) or the nectar from the flowers. This is very common and does not warrant systemic insecticides. Simply spray the foliage with high-pressure streams of water.
Q: Can you suggest some drought-resistant, small ornamental trees that can stand the hot heat. We have an eucalyptus and a California pepper tree. Our backyard is pretty big and neither tree provides ample shade and my smaller flowering plants are suffering from the hot sun. I was thinking of planting two or three small trees in between the flowers to provide some shade here and there.
A: This is a great idea as smaller trees, or even large shrubs, will provide the relief your plants require. Consider small flowering trees like chaste tree, desert willow and Texas mountain laurel. Shiny xylosma and bay laurel are great foliage trees, the latter with leaves that may be used in cooking (bay leaves).
Dennis Swartzell is the marketing director for Mountain States Wholesale Nursery. As an ISA board-certified master arborist and a member of the Southern Nevada Arborist Group, Dennis has been helping Southern Nevadans with their gardening questions for over 25 years. If you have a question about a particular plant, or a general gardening issue, send them to Dennis at treemender@cox.net.