Privets, shrubs, salty soil don’t mix

A: It would be helpful to know what the symptoms are, but I envision that you are experiencing one or more of the following: The shrub’s leaves are green but the edges, especially the tips of the leaves, are turning brown, or the leaves are light green with yellow between the veins.

If you are experiencing these symptoms, it is a sign that the soil is not well-suited to your shrubs. Privets (and many other shrubs) like well-amended, acidic soils. Once planted, it is difficult to change this condition, but I would start by setting the hose near the root ball and letting it trickle to push excess salts away from the root ball. This can be done monthly to aid in salt reduction. You may place some soil sulfur on the surface and cultivate it into the ground. Then place well composted organic mulch on the surface to a depth of 2 to 3 inches. This will help to lower the alkalinity somewhat. I would not apply any more granular fertilizer to the soil.

Consider the application of an acidic, water-soluble fertilizer through a hose end sprayer and apply foliar applications to the shrub. This will aid in the introduction of beneficial nutrients directly to the foliage. What goes on the ground will also help to make the soil more acidic. If the problem persists, consider plants that are better adapted to Southern Nevada like dwarf myrtle, shiny xylosma, or even mock orange.

Q: I have discovered a giant black bug with long antennae. I had one dead branch on my blue palo verde this spring which has been cut off. Did this insect hurt my tree and will it survive?

A: The insect was likely a long-horned beetle, which is native to this area. The larvae do feed on various tree roots, but it is not a widespread nuisance. Although the beetle may have laid eggs near the base of the tree and some feeding may result, I would not be overly concerned about its presence. Unfortunately, there is little you can do to control the insect as most insecticides are ineffective. I would concentrate on keeping your trees healthy. You may wish to contact the Nevada Department of Agriculture for a positive ID. They may be reached at 486-4690.

Q: We just moved to North Las Vegas seven months ago … what a difference. Las Vegas does not have enough trees. Please advise me on what shade trees to buy for our small lot. I want to plant trees that will give shade, not cosmetic plants like palm trees.

A: Welcome to Nevada. I agree with you about the trees. There are never enough. For your tiny yard, I recommend that you plant smaller trees, like those in 5- or 15-gallon containers. This will save you money, and the younger trees will often grow faster than the more expensive ones. There is a free booklet available from local nurseries that will help you decide what species to buy. It is called “Trees for Tomorrow.” For more information, visit www.lvsnag.org. Locate the tab in the upper left hand corner. Be aware that small-stature trees will not provide a lot of shade. However, I would suggest desert willow, mulga, chaste tree, Texas mountain laurel or strawberry tree. Large shrubs also work well. The best time to plant is in the fall so that they become established before the heat of next summer.

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, Swartzell 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 Swartzell at treemender@cox.net.