Q: I am relatively new to this desert environment and I know hardly anything about desert plants. Would you recommend the best book(s) you have read that describe these desert plants? Which are best as decorative lawn plants, when should I plant them and how do I care for them?
A: I would focus on something written for the Las Vegas climate or secondly Tucson, Arizona, and lastly the desert Southwest. Books I suggest are available on Amazon and Abe’s Books as well as other places if you search using the authors’ names.
Linn Mills from Las Vegas and Dick Post from Reno teamed up and wrote a book called the “Nevada Gardeners Guide” that has information split between both Northern Nevada and Southern Nevada. Its focus was to understand both Mojave Desert (Las Vegas) and Great Basin (Reno) conditions, soils and how to manage a landscape growing in them.
Tucson has a similar climate to Las Vegas — a bit warmer and humid in the winter and wetter during the summer months. From here is “Plants for Dry Climates” by Mary Rose Duffield and Warren Jones. It includes desert landscape design ideas as well. The newest edition includes an expanded section plant selection and care.
Keep in mind that our winter low temperatures can get into the low 20s and even the upper teens on occasion. Trees you select for the backbone of your desert landscape should withstand these temperatures or you are asking for trouble. Play around with lesser important landscape plants that don’t tolerate these temperatures but don’t expect them to survive forever.
A solid reference book is the “Sunset Western Garden Book.” It is not specific for the Las Vegas area but does a good job discussing desert soils, desert environments as well as an exhaustive list of plants suitable for advanced gardeners.
I use Chris Martin’s “Virtual Library of Phoenix Landscape Plants,” free online and housed at Arizona State University, quite a bit. Just realize plants discussed are used in the Phoenix climate and soils. Adjust your selection for our colder winter temperatures and not as much heat in the summer.
Several knowledgeable local experts include the Southern Nevada Water Authority that has a searchable database of landscape plants for Las Vegas, called “Find Plants.” It is a good online reference when first looking for possible plants to use.
Q: I spent days dealing with the green residue from a summer of thousands of midge infestation. We live near a pond; I’m not sure if that is the reason for our problem. I’m wondering if they are in the plants in our yard and if we could spray something to stop them before the warm weather comes back in the spring. There are still a few holdouts even now.
A: I am curious about what you are calling “midges.” I know the word, but this term does not tell me which insect it might be. Not knowing the exact critter makes it tough to understand what the effective control might be. Their exact Latin name is not necessary, but I think you need another set of eyes to identify them more accurately.
There are some biological and organic controls that might work if its more accurately identified. I would hate to recommend a chemical spray if you don’t need it.
Catch some of these critters and put them in a jar with alcohol (clear vinegar will work in a pinch) and take them to the Nevada Department of Agriculture in Las Vegas on St. Louis Avenue. See if someone there has a more precise name for them. Phone ahead of time at 702-668-4590 and see if there is someone in the office who might give you some ideas. While you’re at it, ask them what they would use for control. They have access to the state entomologist in Sparks, but it might take a while to get it identified.
Another place to take it is the master gardener help desk. Call 702-257-5555 and take them a sample in a glass jar and see if they can help get the right name for it and possible controls. It doesn’t need to be the exact insect ID name but close enough so we are on the same page.
Once you find out what it is and get some ideas about how to control them, contact me again and let’s go from there.
Q: Some time ago, you mentioned a plant that is used between stones or pavers, and when you step on it, it releases a fragrance. Can you tell me the name of that plant again? I would sure appreciate it.
A: I don’t remember a specific ornamental groundcover that I mentioned but creeping thyme will work, and it does come in culinary and nonculinary types. You can direct seed it in those cracks by preparing the soil with compost, watering the soil to settle it, lightly cover the seed with sand and keeping the soil moist until you see it germinating.
You can use creeping thyme for cooking in a pinch but use new growth. Don’t plant it in extremely hot locations but it will work in an open area without reflected heat from a south- or west-facing wall. Plant it just like you would in a vegetable garden.
Q: These creepy white things keep cropping up out of the ground all over my backyard. What are they and are they dangerous? I am thinking they might be a mushroom or fungus of some sort. I am concerned because, in the past, I had a serious, invasive fungal infection (aspergillus) requiring surgery.
A: Yes, these are mushrooms (fungal) and they feed on decaying wood, wood chips, particles of wood or rotting woody roots in the soil. The wood might be from wood chips used as a surface mulch or signal dead and decaying roots of trees. You might see some in compost piles as well.
Oyster mushrooms, edible types of mushrooms, are commonly grown in decaying wood chips so it can be a perfect habitat for some types of mushrooms. But it’s natural for them.
Several types of mushrooms appear in the cooler spring and fall months after a rain. Most are not poisonous, but that doesn’t mean they can be eaten. The mushrooms seen can range from puffballs to traditional mushrooms to slime molds that look like vomit on the ground. I have been told they can make pets sick if eaten and may require a visit to the vet, but it’s normally not life-threatening.
They are more of a nuisance to most people. To get rid of them and keep them from spreading, vigorously rake the area when they are young and first seen to prevent them from maturing. These mushrooms open up when mature and spread spores that are their seeds for spreading to other wood mulch during rains.
I realize some people are very sensitive to the spores of some types of fungi including mushrooms. Take some pictures of the problem. It is best to check with a physician to be sure.
Q: My gardener said my Carolina cherry laurel died from a pest. He is cutting it out and suggested treating the soil and waiting until March to plant anything new. He is suggesting a holly oak, which sources say can reach 30 to 60 feet in height. That’s quite a range.
A: Most likely the Carolina cherry laurel died due to where and how it was planted and maintained. It is native to the Carolinas (hence its name) and should tell you about its suitability for desert climates and where it might survive in local landscapes.
Holly oak is big, but it grows slowly. It will grow about a foot a year with irrigation and handle lawns well. It is not used much anymore but a good tree for large landscapes, not smaller residential landscapes.
Pick something smaller. Single-story homes should have trees with a 20- to 25-foot mature height. Two-story homes can handle 30- to 40-foot-tall trees. No bigger. This is just too big for most homes.
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.