Q. Is it possible to mix Kentucky bluegrass, ryegrass and Bermuda for year-round greenery and thickness in a lawn? This is the textural difference between Kentucky bluegrass and an old fashioned tall fescue, probably Kentucky 31. A. The short answer is no. But if you are satisfied with a hodge-podge for a lawn that will slowly change over to Bermudagrass in full sun, or where irrigation is weak, then this combo is fine. It depends on the level of quality you are willing to accept in a lawn. Most people want a beautiful lawn and this approach will not produce a beautiful lawn. This is a winter picture of bermudagrass (brown) that has invaded tall fescue lawn area. The irrigated area is too narrow to support lawn grasses and the mowing height was probably short enough to encourage bermudagrass growth. Its the winter so bermudagrass is dormant.             I understand the temptation. Our valley and the Mojave Desert lie in what is called the transition zone for grasses used for lawns in the US. The transition zone in southern Nevada is not too cold for warm season grasses like Bermudagrass and not too hot for the heat tolerant Kentucky bluegrasses, perennial ryegrasses and tall fescue. The transition zone is a perfect place to grow all the grasses but grow them poorly. This is an old map from the Lawn Institute (no longer available online) showing the basic turfgrass growing regions. Green is best for growing cool season grasses like Kentucky bluegrass and ryegrass. The red zone is best for the warm season grasses like bermudagrass and centipedegrass. The yellow zone is ours…the transition zone where both types of grasses will grow.             These grasses are not managed the same either. Common bermudagrass can be mowed less than an inch, hybrid bermudagrass less than half an inch. But Kentucky bluegrass and tall fescue should be mowed at least 2 inches tall. Perennial ryegrass has the most versatile mowing height since it can be mown as low as hybrid Bermuda or as tall as bluegrass or fescue. Your selection of a mowing height will favor grasses that grow best at those heights. Turfgrasses for Urban Mojave Desert Landscapes             The winter months favor the cool season grasses like bluegrass, ryegrass and fescues. The summer months favor the warm season grasses like Bermuda. But bermudagrass is aggressive and will choke out other grasses unless you do something about it. This will require work and money on your part. Lawn Establishment in the Mojave Desert             Golf courses in Las Vegas were pioneers in using a mix of hybrid Bermuda and heat tolerant perennial ryegrass together during the 1990s. But this mixture was managed yearly. If it weren’t, the Bermudagrass would take over. The Bermudagrass was thinned out and heat tolerant perennial ryegrass, like Palmer and Prelude varieties, were sown back into it in the Fall. These management practices guaranteed a solid stand of Bermuda and rye during the summer months. Maintaining Tall Fescue in the Urban Mojave Desert Landscape Maintaining Bermudagrass Lawns in the Mojave Desert

Q. You mentioned on your blog that chelated iron won’t green up yellow leaves when it’s applied to the soil outside of the spring months. Why does this happen? We are a major tree company and see this sometimes. Also, how long should it take to see leaves become green again after we treat the tree with iron? A popular iron fertilizer that takes the shotgun approach is Kerex. It contains EDDHA chelate in small amounts along with iron oxides, iron sulfate, Milorganite and other ingredients that are a hodgepodge of fertilizers.  A. Two methods are used here to green up yellow leaves. It has a lot to do with the chemistry of the soil, more specifically how alkaline it is, whether it is an iron problem or not, and the type of chelate used in the iron fertilizer. It can get hard to predict if it will work or not. You will see later I will sometimes “shotgun” it if I am confident the yellowing is due to iron and the problem can be corrected. This, Sprint 138, manufactured by BASF, is an excellent EDDHA iron chelate and works great but it is expensive. One 5 lb bag is typically over $100. Less expensive EDDHA iron chelates are manufactured by China but I wonder sometimes about their quality. I have seen mixed results with off brands.             If I have the time, I will start with a spray bottle of iron fertilizer to see if an iron application will work or not. Spraying this liquid mixture on yellow leaves will tell me if the yellowing is due to iron or not. But it takes about 24 hours to find out. This is a 1 lb cannister of EDDHA iron chelate but manufactured by an unknown source and marketed by an American company. It costs considerably less than Sprint 138 and works sometimes, and sometimes not.             If the leaves change to a darker green in 24 hours, then an iron fertilizer application will work. Otherwise it’s a guessing game. For some people, 24 hours is too long to wait for an answer. This is another iron chelate labeled Sprint 330 and contains a different chelate called DTPA. It works IF the soil alkalinity is measured less than a pH of 7.6. Most desert soils are not that low in pH and so it does not work in many soils. It costs about half the amount as Sprint 138 so its tempting to buy.             Here’s where it can get tricky. If it is early enough in the year and the tree is still producing new leaves, I can apply an iron fertilizer to the soil, and it should work. If it is later in the growing season and the tree has, for the most part, stopped growing and preparing for next years growth, then the only thing that will work is spraying the leaves with a liquid iron fertilizer. This is another iron fertilizer made from acidified mine tailings that contain iron. If the pH of a soil is low enough then iron will be available to the plant.             If an iron fertilizer is applied to the soil, then the choice of iron fertilizer to use can become critical. If the soil is in rough shape and neglected, then use an iron fertilizer containing the chelate EDDHA. I would, in fact, use that iron chelate fertilizer whenever trees and shrubs are surrounded by rock. Because this can be a guessing game, I only recommend iron fertilizers that contain the EDDHA iron chelate. Its more expensive but I am more confident it will work under most circumstances. Another way of correcting yellowing due to unavailable iron…iron sulfate. It will work as a foliar spray if the iron spray solution has a pH of about 7 or a little above. Works great on lawns. But it will stain fruit, concrete walks and pools.             If the soil is in good condition, then usually any iron fertilizer containing an iron chelate should work. If you are price sensitive and always buy the least expensive product then, because of the soil chemistry, your selection may or may not work. I understand the reasoning, but it is a gamble. Sometimes you win, sometimes you lose. Iron sulfate staining grapes Iron sulfate staining concrete             If you see leaf yellowing about halfway through the year or later, then soil applications wont usually work. You must spray the leaves with a liquid iron fertilizer to cause the leaves to change from yellow to green. This can mean multiple applications of an iron spray. Please read my directions on how to make liquid iron applications to the leaves on my blog to improve your chances of success. Iron fertilizer containing HEDTA chelate plus 3% water soluble nitrogen and potassium for foliar spraying. If the yellowing isn’t due to iron, then the nitrogen will green it up.             What to do? I usually do both treatments, shotgun it, if there is a problem and I want the best chance of success. Two applications can be cheap insurance. If spraying works, it will cause the leaves to turn green overnight. Soil applications might take up to a week to see a change in leaf color and then it will be only in the new growth.             But applying the right iron fertilizer before the leaves come out in late winter or early spring can pay some dividends if you suspect leaf yellowing might occur.

Q. We have a palm tree that is getting taller and is now starting to lean. Should we be concerned about it falling over? A couple different tree trimmers have told me not to worry, but I’m not sure of their judgement. Leaning palm A. If the water is applied to the soil out a distance 5 to 6 ft from the trunk in all directions and two feet deep, I agree with your landscape professionals and not to worry about it. Roots grow where there is water. If water is only available to palm roots two feet from the trunk, then the tree will have a problem staying upright as it gets taller. Ever hear of hurricane palms? These are palm trees that were nearly blown over in typhoons or strong winds and continued to grow leaning. This is a coconut palm near our Family Farm, MoCa Family Farm, in Batangas, Philippines. It was nearly blown over in a typhoon but kept on growing…only at an angle.             One of the jobs of plant roots is to anchor the tree in the ground. Your job is to provide water far enough from the trunk so its roots can grow and anchor the plant. If roots can grow out deeply and several feet from the trunk, the roots will provide enough anchorage for the palm tree to stay upright.

Q. I screwed up in my pursuit of ant control with borax and sugar. It worked well but one evening last week I made the mistake of pouring my mixture right at the base of one of my vines rather than in a plastic bottle cap to keep it out of the soil. Now one of my vines is showing signs of toxic poisoning. I am very concerned about losing the other. I have added some 20-20-20 food hoping this will help recovery. Boron is an essential plant nutrient. Plants need it in very small amounts. Most soils have plenty in them. Borax contains about 11% boron by weight. Thats alot of boron when most plants are quite happy with soils containing 1-2 ppm boron. Thats ppm or parts per million. As a salt, boron is transported to plant leaves where it accumulates along the edges of leaves where water goes into the air, thus concentrating it. A. Ouch. What you are seeing is most likely boron toxicity. Boron is one of the 16 or 17 essential nutrients for plants, but it is needed in extremely small amounts. But if that very small amount is too much, it becomes toxic to plants. The difference between enough and too much is in the parts per million range! Grasses are a little more tolerant of higher amounts boron than other plants.             Boron does not move in the soil very well like other contaminants. That might prove to be in your favor. Remove the surface soil around the plants down to about 4 to 6 inches and get rid of it. Hopefully you removed some boron mixed in the soil as well.             Organics in the soil help to tie boron up and make it less available to plants. Put a fresh soil mix back with 50% compost mixed in it.             Water dilutes salts including boron. Water the heck out of the areas where you applied borax to try and dilute the boron remaining in the soil and push it below the roots. Water, then let it drain, water, then let it drain. Do this four or five times to push salts containing high levels of boron below plant roots. Lastly, pray.

Q. I have a 17 ft. x 2-1/2 ft. raised bed on the south side of my home I would like to turn into an all-season cutting garden.  I will probably use a portion for growing herbs for cooking. I plan to plant flowering bulbs for Spring flowers.  I would like to have other perennials planted above the bulbs to fill in as the seasons progress.  I am open to planting annuals if they can be used for cut flowers for bouquets. What flowering plants would you recommend?  A. Whoa! You must be a very good desert gardener to pull this off! If you are thinking of the pictures in Sunset Magazine and its easy, it’s not. Lots of soil modification, correct planting time of year, differences in exposure to sunlight, wind, shade, plant selection will all be important.             I strongly recommend joining one of the garden clubs in town such as the Chrysanthemum Society or Iris Society and start absorbing information and ask questions. Google the Nevada Garden Clubs, Inc. website and send in a request. A mentor of mine when I first arrived in the desert was a former president of these clubs and she was a great gardener.             Lots of plants can be grown for cut flowers in the Mojave Desert. They favor different exposures to sun, shade, wind, and planting times. Whenever considering cut flowers it requires wind protection, or they will look ratty. Some are bulbs. Some are started from seed and rhizomes. The most successful growers of flowers I know, plant in different locations in the landscape to take advantage of different “microclimates”.              So, if you have not yet developed your desert “green thumb” then start with a small area and experiment before thinking big.  Some spring bulbs to consider include dahlia, canna, gladiolus, and amaryllis. Fall bulbs might include crocus, narcissus, hyacinth, ranunculus, and even tulips if you prechill them in the fridge first or buy pre-chilled bulbs. Consider iris and all types of mums. There are garden clubs in southern Nevada that focus on these plants. Contact Las Vegas Mum Society Contact Las Vegas Iris Society             Many other perennials grow here as well, too many to list, but require different exposures to sun, time of year and wind to perform best as well as soil enhancement and irrigation. Two of the toughest to grow are begonias and calla lilies.  Many thanks to a mentor of mine, Hobby St. Denis, a terrific desert gardener and former President of the Associated ! Much of this information is contained in the book she wrote for the Nevada Garden Clubs, Inc. and no longer in print. And also a publication from the University of Arizona.

Q. I need to block out my neighbor’s intense landscape lighting that pierces my screen of photinia and comes into my yard. I plan to attach Mexican palm thatch to the iron fencing behind the photinia. That extra layer will block my neighbors landscape “headlights”. Should I spray the palm thatch with any insecticide first in the event there are bugs that could invade the photinia? A. It sounds like an inexpensive way to enhance the enjoyment of your backyard at night. Those fronds should last about 2 years before they need replacement. They will last longer with fewer holes created in the fronds when attaching them to the fence. Some box stores offer reed fencing that might save you some work, last longer and is ready for attachment.             I know of no bugs that would be a problem spreading to your photinia from the fronds so no need to spray. I also don’t foresee any future problems using palm fronds except a potential fire problem if they were to ever catch fire. An inexpensive fire retardant is to spray them with a solution of ammonium sulfate dissolved in water.

Q. I just planted a 5-gallon mesquite tree following your advice and was wondering how I should stake it. Also, I was wondering if I should use the deep watering stakes recommended for it? They are plastic, two feet long with holes drilled in it for deep watering and supposed to encourage deep rooting of trees. A. If the planting hole is dug wide enough, the soil used when planting is amended with something decent, then these deep watering tubes are not necessary. If you water your tree deeply, and not daily, the tree does not need them. If you water your whole yard daily including your trees, which I don’t recommend, then maybe there is some benefit using them.  Buy Soil Aeration Tubes?  The problem with digging a planting hole deep when its not needed is making soft soil beneath the tree that may cause it to sink as the soil beneath it collapses and trying to drive a sturdy stake into soft soil and expecting the stake not to move, along with tree roots.             I have not listened to the sales pitch for these deep watering tubes, but I would guess they are marketed to prevent shallow roots from growing on the soil surface. Most trees don’t want their roots on the soil surface. They want their roots to grow deeply for better anchorage in the soil and access to a larger amount of water.  The Problem is Soil Aeration Tree roots need access air as well as water. Roots need to “breathe”. Watering so often that deeper soils stay wet or the deeper soil is very compacted will hinder air from getting deep in the soil. True of clay soils, wet soils and compacted soils. Small trees should have soil amended to a depth of 18 inches, medium height trees to a depth of 24 inches and tall trees, like most of our pines, to 36 inches. Not all Roots are the Same Root depth of trees is controlled by three factors; if tree roots normally grow shallow (its genetics which is mostly the soil environment where it is from), condition and type of soil and how the tree is watered.  These watering tubes focus only on the third factor.  Control root depth with soil amendments and water management . Trees and large shrubs should be watered separately from shallow rooted plants like lawns, flowers and vegetables. This gives these larger plants a chance at growing roots deeply.             Some trees like mulberry and many types of ash have a preponderance of shallow roots. Its normal for them. It is part of their genetics and the environment where they came from. They like floodplains and wet soils. That’s why they do so well in lawns. In some cases, these roots can be removed from the soil surface or covered with mulch.             Some trees grow roots near the surface of the soil where roots can access air better. This happens in heavy clay soils or soils where the planting holes were not dug or prepared well. With heavy clay soils it is best to grow trees on a 12 to 18-inch rise or mound, so the soil can drain, roots can “breathe” and have somewhere to grow. Advice on Digging Planting Holes             I have harped on planting holes ad nauseum, but always dig the planting hole at least three times the size of its container and amend this soil with decent compost at the time of planting. Buy these tubes only if needed.             If the tree is from a 5-gallon container, then it may not need staking. Trees planted from larger containers probably need it. The primary purpose of staking is to keep the roots from moving. Movement of the upper trunk and limbs is a good thing.

 Know which rose varieties have been successful in our hot desert climate and how to plant and manage them correctly.  Attend the annual Rose Show on the afternoon of November 9th at the University of Nevada Cooperative Extension offices just south of the airport on the corner of Windmill and Paradise Rd.  Rosarians will be present to answer your questions about growing roses in our hot desert climate and poor soils from 1 to 4 pm. For more information call the Master Gardener Help Line at 702-257-5555.