Q. When our landscapers installed new water lines for irrigation they cut through two major roots on a Chitalpa tree; one root was 4 inches in diameter and the other 1 ½ inches in diameter. These water lines could have been installed under the roots instead of cutting them. I am not sure why they did it this way. I am concerned about the future health of the tree. A bit hard to see but a large Chitalpa root cut by landscaper. A. If this is a problem for the tree, is a difficult question to answer. Will cutting the roots of a tree cause it to die? Cutting tree roots always damages the tree. Can the tree recover from this damage? The right answer is, it depends. From your description, the root removal done sounds ominous. Tree roots grow where water is applied. If water is applied in shallow irrigations, it leads to shallow roots.             You can typically remove about one third of the total roots with no problem. This is done sometimes when trenches are cut in the soil for burying irrigation lines. When roots are cut. But when roots are cut, about 1/3 of the top should be removed as well. This removal of part of the top puts the top and roots back in balance with each other. How much of the total roots were removed in your tree’s case? That is difficult to estimate. Strangling roots should be removed as young as possible for obvious reasons.             Look at the distribution of water applied for irrigation. This helps determine where the roots might be. Roots grow toward water because the soil is wetter in these locations. If there is a lawn close to the tree, then roots grow vigorously toward the lawn and less vigorously toward its own drip emitters. If other plants are growing near the Chitalpa, tree roots will likely grow toward the majority of drip emitters because there is more water there. Trees growing in lawns oftentimes grow shallow roots because lawns are watered with shallow irrigations. These roots can be removed if they are far enough from the trunk and are not a major root of the tree used for water uptake, soil nutrients important to the tree or used for major support.             At the very least, remove about 1/3 of the top. Remove entire limbs rather than giving it a “butch haircut” and removing the ends of lots of branches. Removing two or three major limbs is probably enough in your trees case. This native mesquite near a river in Jerez, Mexico, sent its roots deep after underground water coming from the river.             As a precaution, I would stake this tree. Major roots of trees are used for tree stability particularly during strong winds. The tree might need to be staked until the roots secure the tree in the ground. I would do it in case it is needed. Don’t wait until the tree starts to lean because of strong winds. Remove the stakes when the tree is stable. This might be one season of growth for smaller trees or up to three years for larger trees.

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 day can reach 30 to 60 feet in height! That’s quite a range. Typical leaf scorch of Carolina Cherry Laurel planted in desert soils in hot locations 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. Carolina cherry laurel probably should never be surrounded by rock mulch             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.

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 fugus of some sort. I am concerned because in the past, I had a serious, invasive fungal infection (aspergillus) requiring surgery. Many different types of mushrooms can appear after a rain and there is wood in the soil or on the surface A. Yes, these are mushrooms (fungal) and they “feed” from decaying wood, woodchips, particles of wood or rotting woody roots in the soil. They are common in the spring and fall months after rains when there is wood in the ground getting wet and rotting. The wood might be from woodchips 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 its natural for them. Sometimes mushrooms grow in woodchips and they look like mushrooms with the stalk that supports the cap             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 which look like vomit on the ground. I have been told by some they can make pets sick if eaten and may require a visit to the vet but its normally not life threatening. Sometimes these mushrooms grow beneath the soil and make fleshy underground balls             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” which are their “seeds” for spreading to other wood mulch during rains. Sometimes they grow in piles of woodchips or compost              I realize there are people 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. Sometimes they cause an allergic reaction or a rash

Viragrow: Soil Mix to Use When Planting Mesquite: Q. I’m digging out an area to plant a Chilean Mesquite and the dirt is really terrible.  I’m going to dig about 6’ diameter, nice and wide,…

Viragrow: Apply Viragrow’s Horticultural Oil 2-3 Times This …: Applying horticultural oil to your fruit trees and woody landscape plants is very important this winter if you want to reduce pests for ne…

Viragrow: Do You Want to Plant in Winter?: You can plant any  cold hardy  tree, shrub or fruit tree during the winter (except palms) but don’t forget the mulch! Surface mulches …

Viragrow: How to Eliminate Pests While They Sleep: December and January are the best times to go on the offensive and reduce pest problems for 2015. Most people wait until there is a proble…

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 to plant them and how to care for them? A. I would focus on something written for the Las Vegas climate or secondly Tucson, Arizona and lastly the desert Southwest.             Tucson has a very similar climate to Las Vegas; a bit warmer in the winter and a bit more humid and wetter during the summer months. Tucson is in the Sonoran Desert which gets 250% more water (about ten inches of rain each year) than our Mojave Desert (four inches of rain each year) and generally has better soils.             Adjust books not specifically for the Las Vegas area to our climate and soils by recognizing that our winter low temperatures can and frequently get into the low twenties 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 landscape plants that don’t tolerate these temperatures but don’t expect them to survive forever.             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. Their book is available on Amazon and Abes Books if you search using the author names. It would be a good book for Pahrump, St. George and Kingman, Arizona besides Las Vegas and Reno area.             Another book I used in the past is Plants for Dry Climates written out of the Tucson area by Mary Rose Duffield and Warren Jones. As well as plants, it includes desert landscape design ideas. It is also available on Amazon and Abes Books. The newest edition includes and expanded section plant selection and care. The original version presents a concept on desert landscaping called the minioasis landscape design concept which I really like as well as landscape plants that are successful here. It applies to any of our desert climates including the Chihuahuan, Sonoran and Mojave Deserts of the Southwest but less to the Great Basin area.             A solid reference book you should have in your library 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 and their descriptions suitable for many different kinds of Western environments.             As far as free websites on plants online, I reference Chris Martin’s Virtual Library of Phoenix Landscape Plants housed at Arizona State University quite a bit. Just realize its focus is Phoenix climate and soils, is 5 to 10 degrees warmer in the winter and not quite as hot in the summer. It is perfect for Laughlin, Bullhead City and Lake Havasu, Arizona as is. It is excellent for Las Vegas selections but just keep in mind the temperature limitations between Phoenix and Las Vegas. This website doesn’t pull any punches on landscape plant shortcomings and how well they perform in desert climates and soils. Once you have made a plant selection, it is a good bench check on how it will perform here.             Several knowledgeable local experts like the Southern Nevada Water Authority (SNWA) searchable database of landscape plants for Las Vegas, called “Find Plants”. It is accurate with information presented on plants but I find it somewhat cumberson to use at times. It is a good site when you are first looking for possible plants to use.

Plants have a unique way of communicating to us what they need. Learn how to understand them on this podcast of Desert Horticulture.

Lots of fruit trees are being ordered for spring planting now. These are bareroot trees, some with a known rootstock. Besides Grow Organic you have Bay Laurel to look at. They will ship early in 2020 so have your compost ready, your hole dug, a stake to keeps the roots from moving and chicken wire if there are varmits around that might want to nibble on it after its planted.