Large pine trees need extensive deep watering

Q: What is your opinion of pines as landscape trees in our desert climate? We have quite a few planted in our complex and our HOA is discussing whether we should get rid of them or not because of their liability and water use. Our landscaper tells us they have borers.

A: I’m a little suspicious of the borer diagnosis in pine trees since it is rare for them. Have that diagnosis confirmed with a second or third opinion. Aleppo pine gets a blight that causes browning of needles and entire branches.

From a distance, this can look like borer damage. So far no one has discovered the cause of Aleppo pine blight or how to control it but it’s thought to be related to irrigation and not resulting from a pathogen or borers. Aleppo pine blight is so common in the Las Vegas Valley that if a pine tree has brown branches, it is an Aleppo pine, not Mondell.

My opinion of pine trees used for landscaping in the desert is mixed. I don’t think large pine trees should be planted here, but I do understand their light shade value once they have become established and mature.

What makes me hesitate is their removal. I’m not sure if the shade they produce is worth the extensive deep watering needed to keep them healthy and upright against strong winds. In some lower elevations in the valley, these large pine trees with extensive roots may have tapped into shallow groundwater that could help with irrigation and staying stable.

Removing existing, mature pine trees from the property will increase the resident’s electrical costs used for cooling during the summer months. I would recommend that you transition your landscape to smaller, desert-adapted trees that shade the south and west walls of your buildings and then possible pine removal. Once established, their shade will substitute for the pine trees and help reduce residential energy consumption.

It would be far better to plant smaller pines such as pinion and Italian stone pine if a pine tree is desired. Japanese black pine is sometimes recommended but look around. Do you see any older Japanese black pine in the valley? Many have been planted here. It doesn’t survive in the desert for any length of time so I would discourage planting Japanese black pine here.

Q: Early in the growing season I saw small clear droplets on my grapevines. Would you happen to know what is the source of these drops? I have had leafhopper issues in the past, and I was concerned they might be insect eggs.

A: Not too many people see what you saw. We are too busy to notice. These droplets are tiny and difficult to see. Not all kinds of grapes seem to have them. You might see them on Concord or Thompson seedless. Nothing to worry about but it is an interesting phenomenon.

They are called “grape pearls” or “sap balls” and not related to insects or diseases. However, they do look like insect or mite eggs. Leafhopper females lay their eggs inside the leaf veins so there are no eggs of this insect to see on the underside of leaves.

These droplets are pushed outside the leaf when the vine is full of water and experiencing rapid new growth. They are usually found on the undersides of leaves or on young stems.

It reminds me of the water droplets pushed out of turfgrass through hydathodes in the spring during cool weather. There is so much water present on grass leaf blades that golf course superintendents would send someone out with a bamboo pole to whip the greens and remove the dew on the grass.

Don’t be concerned; just ignore them. If your grapevines are dense, shake the vines so water drops to the ground. Otherwise, they will dry normally and disappear as the daytime air gets hotter and drier.

Q: Is it possible to transplant chollas and wildflowers? I live in a subdivision that will be excavating these beautiful plants to pave streets so I was wondering if it’s possible to transplant them and if they will survive after transplanting.

A: Yes, it is possible to save many of them, but it will be a challenge and you have to know what you’re doing. Years back I worked with a former Nevada Department of Transportation landscape architect in preserving native plants when the road to Searchlight was widened. They attempted to rescue valuable native plants prior to construction by excavating and placing them into a nursery until they could be relocated.

Contact your state’s Bureau of Land Management, Native Plants Program for information about native plant rescue. Native plants are protected and permits may be needed.

It’s not an easy task and requires specialized knowledge. Not all the plants will survive after being rescued. Be prepared for that. There will be some plant mortality regardless of how careful you are. Native plants have extensive roots that developed for survival under extreme desert conditions of low rainfall and high temperatures.

A local landscape company called Trident Landscape Management has experience relocating native plants into residential landscapes. It’s the only one in the area that does, to my knowledge. The owner has experience and knowledge about rescuing and using native plants from our Mojave Desert and has participated in relocating them. I would recommend involving them so they have the best chances for survival.

Annual wildflowers are probably best saved by collecting seed. There are a few Mojave native woody plants and perennials available in local nurseries. The Nevada State Division of Forestry has a nursery in Floyd Lamb State Park that propagates and sells many native plants to the public. Consider supplementing your landscapes with these plants if they are not available through local nurseries.

Q: I have a cactus garden that faces west. Every summer I hang sheets on a clothesline in front of the cactuses because it always looks as though they are starting to burn up from the direct sun and heat. If I don’t protect the cactuses this year, will they die?

A: It’s difficult to say without knowing which cactuses you have. Not all cactuses are the same and handle the Mojave Desert with ease.

Cactuses available from retailers are from a wide range of habitats. Some of these habitats are not as environmentally extreme as our own Mojave Desert. These cactuses may show signs of stress when plunged into our Mojave Desert climate and soils. Cactuses that originate from other areas may be more tender to Mojave Desert conditions. Discover which cactuses you have and their place of origin.

Of course, cactuses native to the Mojave Desert have a much better chance of survival without protection than cacti imported from other deserts with a milder climate. I would recommend using these if available.

You might have to relocate some of your more temperamental cactuses into a milder microclimate in your landscape. Find an exposure on the east side of the home or under some light shade. Most cactuses can be relocated during the heat of the summer months.

Q: I have a contorted jujube, which is partially self-fruitful. I acquired a Lang jujube, which needs a pollenizer tree. I don’t really have space to plant the pollenizer tree close to it. What is the maximum distance I can plant a pollenizer tree from the other?

A: Jujube performs extremely well in our hot desert climate. It is also called Indian fig or Chinese date. It’s a good fruit tree selection if you like the fruit. Even if you don’t like the fruit, it’s a vigorous landscape tree if it is irrigated.

The term “beeline” is a good one to remember. It’s more important to have the pollenizer tree in a straight shot from the other tree and not around a corner. Bees travel in straight lines for the most part.

These trees are pollinated by honeybees and other insects during the early spring and summer months. So, if you don’t have pollinators actively working your landscape then fruit production will be low even if you have a pollenizer tree.

Attract pollinators into the landscape by planting flowering herbs like rosemary and provide clean water they can haul back to their hive. Birdbaths work with some rocks placed in the water as landing pads for the bees.

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.