Q. How can I get rid of spurge in my vegetable garden?  I have been hoeing it and hand pulling it just about every day, but it appears to be getting ahead of me this year.  I do not use any chemicals in my garden, so that is not an option. A. Shade. Spurge hates shade.  What is Spurge? Spurge is a pernicious weed; it hugs close to the ground when it grows and germinates rapidly from seed it produces in less than 30 days during summer months. It can also grow new roots if it is hoed and left on top of wet garden soil. It must be removed after hoeing since this plant produces seed continuously. Pepper with horse bedding for mulch.            Its strengths are how much seed it produces, how fast the seed germinates and its ability to root in moist soil once it’s been hoed. But its big weakness is shade. By that I mean it doesn’t take much to shade it out. If the garden space is full of plants and producing a lot of shade, spurge has a difficult time.            There are several types of spurge, but I think yours is prostrate or creeping spurge that hugs the ground and makes a tiny drop of white latex when the stem is broken. And of course, lots of seed! Weeds in onions controlled with horse bedding as mulch Control Most Weeds with Mulch            Weeds rob watered light. That’s also their weakness. So, use a surface mulch (½ inch deep) thick enough to shade the soil to defeat it. The application of anything deep enough to keep light from getting to the seed will keep it from growing.  Horse bedding is nice as a mulch because it decomposes quickly when its wet.            Apply this surface mulch after planting or the after the seed is up. Garden mulch includes horse bedding, straw, paper (sheets, strips or shredded), cardboard, or anything else that blocks light from reaching the seed.            Apply this surface mulch early in the season and hoe the soil surface before you put it down. Spurge seed produced during August and later will not germinate until next year. But any older seed still lying on the soil will germinate if it gets water and light. By the way, most annual weeds like spurge (and many others) hate mulch.

Q. The fruit from my nectarine had a lot of “sores”; spots with tiny “bubbles” of hardened fluid. Yesterday, early evening, I sprayed the tree with “soapy water” in hopes of improving the problem. A. Your nectarine fruit has damage from Western Flower Thrips (WFT). That’s one of the reasons I don’t plant too many of them. WFT are hard to control without spraying frequently and soapy water alone won’t do it.  Spraying with Spinosad insecticides weekly until harvest, starting after the flower petals have dropped, has given the best control for me.            I alternate Spinosad with Neem oil, and soap and water sprays so WFT don’t build resistance to it so easily. Peaches are easier to grow without spraying as much because of their fuzzy skin. View my posts on this on my blogPyrethrin Doesn’t Kill Thrips Fruit Scarring Can Be Prevented

Q. The class-action lawsuits against the weedkiller “Roundup” claims it can cause lymphoma. Nonetheless, nurseries and big box stores still carry it and even promote it. Isn’t there a safer weedkiller? I have been using “BurnOut” made by Bonide which is promoted as being pet and people safe. Why is it so hard to find? Roundup is carried by many so-called box stores and is still a popular home weed killer.  A. Products like “BurnOut” are not required to show “efficacy data” before entering the consumer market. “Efficacy data” demonstrates to the regulatory agency that it does what it says it does. It’s a form of consumer protection. There are other companies besides Bonide thatproduce products like these. EPA’s opinion on the safety of Glyphosate.            There is a list of ingredients considered “organic” and exempt from regulationby the federal Environmental Protection Agency (EPA).  Each state determines if these products should be sold or not through whatever regulatory agency is responsible. Efficacy data may or may not be required by a state.            “BurnOut” contains citric acid and clove oil as active ingredients. “Roundup” contains glyphosate as its active ingredient. “BurnOut” is a weedkiller that kills by contact. “Roundup” moves inside the plant and is therefore considered a systemic weedkiller. If you look at both labels, “Roundup” must demonstrate that it does what it says it does. This requires EPA registration. There is a federal registration number on the label showing it has met that requirement.            Citric acid and clove oil are considered “organic ingredients” and do not require the submission of efficacy data to the federal EPA. There is no federal EPA registration number on the “BurnOut” label. Also, PPE (Personal Protective Equipment such as gloves and eye/nose protection) is not required when using products like “BurnOut”. You must wear PPE when using “Roundup”. Why Not as Available?            My guess is that products such as “BurnOut”, as well as homemade weed killerrecipes promoted on the Internet, are “contact weed killers”. Whatever plants with leaves you spray, you kill. “Roundup” is a systemic weedkiller that mostly targets grasses but kills many other plants as well and kills the roots as well (systemic) so there is little to no regrowth of perennial weeds.            Why products like “BurnOut” are not found more? I think a lot of it has to do with the investment the company makes when developing these products, in many cases millions of dollars. I don’t believe Bonide does not have to invest as much money and show “efficacy data” when developing and marketing a product like “BurnOut”. I will handle this in more detail on my blog. Glyphosate vs Roundup vs Health

Q. Is there a simple way of stopping or preventing the volunteer trees, i.e., new tree growth that suddenly starts growing near the base of original tree?  Root suckers can pop up at any distance from the tree. They can be used for propagation but remember, as in this case, the suckers are clonse of the rootstock and not necessarily the tree on top (scion). A. Some plants grow “suckers” at the  base of the plant and others produce suckers, or new growth, a distance away from the plant.  If roots of suckering plants find water and it is out in the open with enough sun, they will sucker.  Oleander suckering from its base (crown). This is the difference between suckers arising from the stem or trunk (sometimes called the “crown”) and growing from the roots. Plants that can grow as a bush sucker from the crown. Plants that forms “thickets” grow suckers from their roots. Roots suckers are common to some plums and jujube as well as landscape trees like elm. Jujube suckering several feet away from its trunk. Several trees have root suckers like Jujube when they must survive fires.            So far, the only practical way to eliminate them is to slice the roots and remove these plants, roots and all. To prevent diseases found in the soil from invading the tree roots, allow these cut surfaces to heal 24 hours before burying them again.

This list was previously put on my blog years ago and I have been asked about updates. The varieties listed here were tested in North Las Vegas with at least five trees per variety for at least 5 years before they were given a rating and the “green light” for planting. Some didn’t make it, either because of winter cold temperatures (citrus, Mexican nopal cactus), possible low humidity problems (sweet cherries and ‘Hachiya’ persimmon) summer high temperatures (filberts, rhubarb), and poor growing conditions (filberts, rhubarb, blueberries, some blackberries, raspberries).  Just because they didn’t make it in North Las Vegas, try it in your microclimate. They might work and please let me know. Give them at least three growing seasons (preferably 5) before you claim a winner.   Citrus does grow in Las Vegas. It just depends on the microclimate of where its growing. I would like to thank Dave Wilson Nursery (particularly Tom Spellman and Ed Laivo (formerly at Dave Wilson and now at Burchell Nursery) for supporting this project. About 95% of the fruit trees planted were donated. I would also like to thank Tony Valenti , Owner of First Choice Tree Service for believing in my project enough to donate woodchips to use as a soil mulch when local tree companies were against it. They donate woodchips to the University Orchard still in 2020. which is then donated to the community through the Community Mulch Pile. Community Mulch Pile at the University Orchard in North Las Vegas. There is a second community mulch pile located south of McCarren Intl. Airport. Call 702-257-5555 during the week and get the details. What is a Microclimate? Microclimates in landscapes can have different temperatures during the summer or winter (hot walls, shade, freezing temps), humidity (lawn, pool, fountain), sunlight (reflected glass), differences in wind (channeling between buildings) and all these affect plant performance in the desert. Plants do best when everything is still, plenty of sun (but not too much), temperatures warm, and humidity moist. Citrus Citrus include kumquat, lemons, limes, oranges, grapefruit and others. By now you should know that kumquat is probably the most cold hardy of the group, followed by Myers Lemon, Grapefruit, and others. Citrus is not included here because we lost the citrus to low winter temperatures (below freezing weather) before the five years was up. However, in some locations around Las Vegas citrus was thriving. At another location, the same thing happened or they were heavily damaged by the winter cold. So be careful planting citrus here. The second problem with some citrus are January, February and other late spring freezes. These freezes eliminate some or all of the fruit coming from citrus flowering then. Low Humidity Another characteristic of the Mojave Desert is its low humidity. Very low humidity. This is a problem for some fruit trees. Sweet cherries and ‘Hachiya’ persimmon also were not listed, because they seldom produced much fruit unless there were spring rains. Yet in some locations in Las Vegas sweet cherries produced every year! I think it was because of the low humidity. Residences with lawns or a swimming pool close by produced fruit. Some tropical species also have problems with fruit set at a humidity lower than 30%. It is believed to happen because of the drying of pollen. Go to my fruit tree list (former blog post) Request a copy of my list (email)

This is the current (2020) production coming from peaches and apricots at The Orchard at Ahern. The Orchard at Ahern is located between Bonanza and Washington off of Clarkway. There are about 3000 fruit trees planted in this 8 acre orchard only 1 1/2 miles from the Las Vegas Strip. The Orchard at Ahern is a 3000 fruit tree orchard located on Ahern property only 1 1/2 miles from the Las Vegas Strip. Apricots pruned for height control spaced at 10 ft between trees and either 10 ft between rows or 14 ft for equipment movement. Apricot production. Apricots and aprium varieties totaled about ten different varieties with chill ranging from a little over 200 hours to over 700 hours and no fruit thinning. Apricot and aprium varieties include Flavor Delight, Leah Cot, Summer Delight, Katy, Chinese, Royal Rosa, Blenheim, Flavor Giant, Gold Kist among others on semi dwarfing Citation (preferred) and Myro 29C. Peaches were on the same tree spacing as apricots and pruned to the same height. Peaches were thinned by pruning when they were dormant during the winter. No hand thinning of individual fruit was done. About 24 varieties of peaches and six varieties of nectarines were planted about four years ago. Again our favorite rootstock when keeping them under ten feet tall is Citation semi dwarfing rootstock.

Q. We Live in the Phoenix, Arizona area and have two 10’x10′ planters made of pavers and want to plant ‘Red Push’ Chinese Pistache in them. I am worried about damage to pavers from the roots. Irrigation would be from drip irrigation system on a timer. One of the planters for a Chinese Pistache tree A. ‘Red Push’ Chinese Pistache tree can get 50 to 60 feet tall with irrigation. In my opinion, this tree is too tall for most residential properties. You need a large landscape, a park or city streetscape to accommodate that size. Read what Chris Martin from ASU has to say about Chinese Pistache in the Phoenix area. The size of the planters should not be a problem when planting Chinese Pistache if using a soil coarse textured enough for good drainage and not planting shallow rooted flowers in there that require frequent, light irrigation. If planting something else in that planter, select plants that have deep roots or that don’t require frequent irrigation. I would select a smaller tree. I have the feeling you selected that tree because of its fall color. There are other reasons for tree selection than just one trait. What sizea tree is needed for those planters? 20 feet? 30 feet? Remember, larger trees usually use more water. What shape should it be? Arching? Round? Upright? The Phoenix area has some pretty good wholesale nurseries that grow plants for the desert including Mountain States Nursery and Arid Zone Trees. Take a look at what they have to offer.

Thinning fruit, or fruit removal so the remaining fruit become larger, does not have to be a mystery. It is a management process that you must do for most fruit trees. If you don’t, the remaining fruit will not become larger. But on some fruit trees it doesn’t work. Learn which ones it doesn’t work on and why in this Desert Horticulture Podcast.

Learn why Bottle trees are NOT desert trees, managing spider mites in home landscapes and the reasons for the yellowing of plants growing in desert soils.

Our light intensity is very strong in the desert. Some thin barked trees and shrubs get sunburned if they don’t have enough protection from strong sunlight. The natural way to protect plants from sunburn is to allow these plants to shade their own trunks and stems with leaves. Not providing enough water can thin out the canopy of trees and shrubs and encourage sunburn. Sunburn, like on this ash tree, starts out as a discoloration of the wood. Plants that typically sunburn include many of our fruit trees, mostly peach and apples. Ornamental trees and shrubs also get sunburn. Plants that I see with sunburn include Japanese blueberry, locust trees, ash trees, Indian Hawthorn, and others. Sunburn can happen to fruit, too. This yellow apple has the first sign of sunburn on the fruit facing the sun. Severe sunburn causes the plant to die on the side exposed to the sun. Bark on this side is loosely attached to the trunk. When you pull this bark away from the trunk you may see oval-shaped holes in the wood. These are exit holes of borers. Removing the bark also removes hiding places and birds have a better chance picking them off when they emerge. The side facing the sun dies under severe conditions and boring insects can invade the living parts on the edges of the damage. Eventually this becomes part of the tree that dies. Having rock mulch around plants that do not like rock mulch reduces the number of leaves and increases the chance of sunburn. Plants that do not like rock mulch, like the ones I mentioned above, will develop an open canopy, leaf loss, and sunburn. In the case of sunburned fruit the area darkens as the sunburn worsens. What’s the problem with sunburn? When humans get sunburn we recover. When plants get sunburn, particularly in a desert climate, they frequently decline and die. Attack by boring insects, or borers, is the first phase after sunburn damage. The borers create more leaf loss which increases sunburn. At this point the plant falls into a death spiral. The side of the branch or trunk facing the sun has the most damage. In this Bottle tree it is the upper surface of the limbs. Use surface mulch, particularly wood chips, and not bark mulch. Don’t water trees and shrubs daily. Water them two or three times each week during the heat of the summer. Reduce the number of times per week during the cooler months. When they receive water, it should water the roots to a depth of at least 12 and preferably 18 inches.