xtremehorticulture – Page 3 – Xtremehorticulture

Planting a Lawn in the Desert

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Q. I’m getting ready to plant a small plot of fescue grass (seed) at my home. Do you recommend any soil amendments to the soil for a healthy lawn? A. Not really if the soil is workable and medium brown when it’s wet. It should not be difficult to dig. Are the amendments intended to improve the soil there or do you have to bring in additional soil up to a finished grade? If not, then just seed the area. Grass does not need soil that is “soft”, but firm. Core aerification (after the lawn is mown at least twice) will open the soil and help the roots grow deeper. Do that anytime. When you construct the lawn area, make sure it is at least 10 feet x 10 feet and square or at least rectangular. Water does not travel easily in other than straight lines. If you use any curves, make them gentle and big so they are easier to water. Lawns growing in the desert are all about water!!! Seed I am assuming you are using tall fescue. Select expensive grass seed, not cheap tall fescue seed. Stay away from K31 or Kentucky 31 grass seed. K31 grass seed is less expensive than other tall fescue seed. Seed at a rate no less than 7 to 8 pounds of seed for every thousand square feet of lawn area. Whatever you do, don’t exceed12 pounds of fescue seed per 1000 square feet of area. All Seed likes Firm Soil Not hard, but firm. How do you know if it is firm? It should be easy to dig and at least medium brown in color. Clean up (free of weeds) the area to be seeded. All Seed Prefers Contacting the Firm Soil All seed likes to grow in contact with the soil. Cover the soil (put a light blanket on top of the seed) and seed with no more than ¼ inch of sand or compost. Avoid using a “thick blanket” covering the seed. In other words, don.t suffocate the seed! Plant big seed in the soil (beans, corn, etc.) Plant small seed (carrots, celery, etc.) near, or on top, of the soil. Watering the Seed Irrigate until you see standing water then stop. Do this no more than twice a day, morning and then afternoon to get the seed to germinate. Seed only needs to stay swollen with water. The soil around it can be dry. The first to come out of the seed is the young root. It has to penetrate the soil so make sure it is not hard. Once the seed germinates, water next when your footprints on the grass stay laying down. Seed during Feb – April or late Sept – early November. Avoid germinating the seed during the heat of summer. Mowing If you install the irrigation system yourself, make sure to check the pressure or call your water purveyor in your area and have them look at the water pressure for your address. The irrigation heads should spray water from one head to the neighboring heads. Unless it is always windy or watering a 30% slope. Then irrigation heads are closer than that. Never mow your fescue lawn lower than 1 1/2 inches. When mowing, mowing high is better than shorter. Mow closer to three inches. Mowing patterns establish “striping” and the grass “grain”. Mow in the same direction and spots to produce “striping”. If you don’t want “striping”, mow in opposite directions and alternate the spots where you start. After you mow it three or four times then rent a core aerifier and bring cores to the surface. Rake them up. Follow that feat with a fertilizer high in phosphorus (the middle or second number. Oftentimes 16-20-0 fertilizer is used. Put this fertilizer down following the label on the bag. Don’t exceed this amount. Once the Lawn is Established For the best water management, level the soil and make it as flat as you can. A tall fescue lawn will need anywhere from 7 to 8 feet of water every year! You will apply more water than that because the uniformity of your irrigation system (how evenly water is applied, using stationary popups, the best you can do is from .6 to .7, golf courses with larger heads can be closer to .95 or 95%) is from 60 to 70%, The best irrigation heads (stationary popups) for tall fescue growing in smaller areas should “popup” to four inches above the lawn (not three or two) and be flush with the surrounding soil. For hybrid bermudagrass, they can be watered with two-inch popups. How the irrigation system is installed has everything to do with the water’s “uniformity of application”. After the lawn is established (mowed three or four times), 12 to 15 minutes (this time can be split into multiple times with an hour or less between them but totaling from 12 to 15 minutes total or per day) is usually long enough to set the irrigation timer. Change the days per week only, not the number of minutes. Water early in the morning (after 2 or 3 am) and finish watering before the wind of the day starts (sunrise). Don’t water at the beginning of night or you may get a lawn disease! Fertilizing Lawns Fertilize the lawn four or five times each year and avoid the heat of summer months (don’t forget to fertilize on Thanksgiving use that as one of your days). Core aerify once a year. Never ever mow less than 1 1/2 inch tall. the best lawn fertilizers are in a ratios of N-P-K as 3-1-2 or 4-1-2. Examples are close to 21-7-14 (3-1-2) or 20-5-10 (4-1-2).

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Eastern Redbud is More Common

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Q. Attached is a picture of a redbud tree. Since we are from back east, we weren’t sure how far west it “grew” (turns out its territory is east and Midwest). We would like to consider a flowering tree like this in our front yard. Any suggestions? A. What you are seeing is probably an Eastern redbud (Cercis canadensis). It is native to the US and Canada and is a bigger tree (to 30 feet) than desert redbud varieties (15 to 25 feet). All redbuds do well in canyons and as an “understory tree” (grows in the shade of other trees). Very cold tolerant. That’s what the local nurseries will carry unless they grow a different redbud themselves. Eastern redbud has carved a niche and so most growers will sell that tree as their own “redbud” selection. You are better off paying a little extra (or getting a smaller plant and letting it grow). Either Mexican redbud (C. canadensis var. Mexican) or Judas tree (C. siliquastrum) will still need an extra irrigation in the summer even though they are both native to the desert southwest (xeric). Water this tree less often but just as deep. Watering less often and its size are where water savings occur.

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Water Needs of Tomatoes in the Desert

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Q. I’ve been growing about 25 tomato and pepper plants for over 20 years in town. I’ve always just guessed, and some years are better than others, but I wonder how much water I need to get the max effect without wasting the water? How many times a day in the spring when I’ve just planted and how many minutes on each setting? Also, in the hot summer, I do cover the tomatoes, so they don’t get sunburned. A. I can only guess. No one has “discovered” the water use of vegetables in Las Vegas, much less what happens to tomato water use when it is covered. Probably what is more important is the quality of the vegetables and how they are managed (fertilizer, thinning, shading by neighboring plants, etc.). When covering vegetables use 30 to 40 % shadecloth. I can tell you how I water them! With warm season crops, they need warm soil. I warm the soil with clear plastic before planting. I use half inch drip tubing with built in emitters, 12 inches apart. I “triangulate” the location of the emitters so I get better distribution of water. The “drip lines” are also installed 12 inches apart and pulled tight. I use emitter spacing for planting distances. When they are just seedlings, I water and fertilize them (every three to four weeks) to get growth. When plants are mature, I water them until the soil is full of water. Then I wait for the plant to use up the water. Plant water use is dictated by four governances; how bright it is, wind speed, temperature, and humidity. Those are the four ingredients, measured by weather stations, that predict plant water use. Research has discovered how to apply these four factors into a mathematical equation used to predict water use of a specific plant. This plant’s water use is then multiplied by another number to list a specific plants water use (such as tomatoes, eggplant, peppers, etc.) Each vegetable has specific water use (plant size) that must be “discovered” by research. This depends on the time of planting, plants size, vigor as it grows, and other factors.

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Q. What should I be doing now to control borers in my African sumac? A. Make sure there are borers present and has been correctly identified and not just guessed at. I have not seen damage to it from landscape borers. That doesn’t mean it doesn’t happen but I just have not seen it. Imidacloprid can be used protectively or if the “landscape borer” problem is present. If the borer has caused extensive damage to the tree, you may have to “weigh” whether it is worth applying it or not. Sometimes replacing the tree is the more profitable solution. Unlike peach tree borers, this “boring insect” is in the tree, not the soil. Use insecticides or pesticides that contain imidacloprid as an active ingredient. To find if imidacloprid is in the package, find the active ingredients listed on the front or back. The imidacloprid liquid mix can be used as a soil drench only if it says it can be used as a soil drench on the label. For me, soil drenches are the most effective way to apply it because plant roots were designed for the uptake of liquids. Other methods of application exist. To avoid any references to CCD (Colony Collapse Disorder) and honeybees, make applications after the tree has finished flowering to minimize any CCD to pollinators. Since African sumac was made available from south Africa, the flowering of this tree is during the winter. The time to apply a root drench is any time after growth begins in the spring and the tree finishes flowering.

What Caterpillars to Control in March

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Q. What caterpillars should I be controlling now? I know they will start becoming a problem soon. A. Watch your temperature guide like your temperature app on your phone. Watch your vegetables or fruit trees. The principal insect that infests many vegetables in the tomato family as well as grapes is the hornworm. If the fruit is not yet present, they will eat the leaves as it gets larger. Once the fruit is formed, watch out! A hornworm usually has a spine on its rump and can get as big around as your thumb as it eats. It stats small when its young but will get about 4 inches long as it matures. The adults will be present now. About a month or two from now I will stand still for about fifteen seconds until I see leaves move. That movement signals me I missed one and that one will be thumb sized! Any gardener who has been gardening for a while has a horror story or two about hornworms. The tomato hornworm that causes damage is the immature form, the larva (caterpillar) of its adult moth. The adult form of this insect, the hummingbird moth (or sphinx moth), normally hovers around plants (like a hummingbird) when it starts to get dark. The moth form of this bug causes no damage. Nada. In fact, it is intriguing to watch. The moth comes early first. The hornworm larvae come second and get bigger and bigger. Another “worm” or “caterpillar” that causes problems is the much smaller tomato fruit worm (aka corn earworm). It causes damage after the fruit has formed. For us, the tomato fruit worm is less of a problem than the hornworms. It will feed on the leaves as well but prefers to make holes in the fruit of tomatoes, peppers and eggplant after they formed. Control Both are controlled with the same products, either a Bt product (Bacillus thuringiensis, a natural control product) or Spinosad product (another natural control product) sprays or dusts. The spray lasts about 7 to 14 days depending on the weather. Look at the label. Start spraying soon after you plant tomatoes and repeat Bt sprays about one week apart or more often. Spinosad lasts longer than Bt products. Spray about three weeks apart. Make sure to cover the undersides of leaves. It may pay to add a sticker/spreader to the spray mix.

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Tree Aloes From Africa or Madagascar

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Q. Do tree aloes survive in Las Vegas especially any of the tree aloes from Africa or Madagascar? A. “All cacti are succulents but not all succulents are cacti.” That is a cactus axiom. In other words, there is more that restricts geographic distribution of cacti than whether they are succulents or not. Succulents have a wider range of habitats than cacti. Many succulents are “arid” in their climate extremes and some cacti are meant only for deserts. Another axiom is that, “All deserts are arid but not all arid areas are deserts.” Just because its from somewhere arid doesn’t mean it will survive in a desert. Even some cacti from South America struggle when planted in the Mojave Desert primarily due to differences in light intensity and temperature extremes. Plant tree aloes on the east side of a landscape near the shade of a building if you want to be safe. Use wood chips as a mulch or plant them with compost. Never plant them in full sun. An example of climate related damage is the damage of desert climates to Spanish bayonet, a smaller “tree aloe” that is arid. Another native yucca to the east coast is Spanish bayonet (depends on who is talking, Yucca aloifolia or Y. gloriosa). It is a woody evergreen shrub also native to the Atlantic and Gulf Coasts of the United States. Unfortunately its common name is also aloe yucca, dagger plant, and Spanish dagger. The Spanish bayonet should have dark green, stiff, dagger-like leaves with sharp tips that can pierce through thick clothing. It can grow up to 15 feet tall, but often flops over from its own weight. The Spanish bayonet should produce large (1-3 feet in length) showy white flowers that droop downward. In the Mojave Desert however it yellows and scorches when planted in full sun and when soil organics are running low. Again, with few exceptions, most tree aloes grow best in warm, dry, arid, climates; warmer than the Mojave Desert but without the high light intensity of direct sunlight. Another thing our desert climate has against tree aloes are our temperatures. Those temperatures may or may not be changing. Scientists are not sure. Some tree aloes can tolerate temperatures below freezing for short time periods. Others can’t. Tree aloes have at least four things going against them in our climate; they need water, they need some soil improvement, they should avoid high light intensities, and avoid the low temperature damage they get during our winters. Temperatures are Changing It’s not tropically wet like Madagascar yet, but if you have had sweet oranges (‘Valencia’, ‘Washington’) that survived our winter temperatures then maybe you are okay at least for a few years of growth. How many? Not sure. During the winter of 1989-1990 we had temperatures as low as 12F at the Painted Desert golf course. Those temperatures would have killed all citrus, including the cold hardiest types. Citrus, like aloe trees, is considered at the least subtropical. Select the most winter cold tolerant types of tree aloes to be sure. Water Water is added with periodic irrigation. How often? Not sure but the taller the plant the deeper and less often water is needed. It depends on the soil and the type of tree. Add more water and irrigate wider as the tree aloes get bigger. Soil Organics Our soil is ultra-low in soil organics. Add between 10 to 20% (normal amounts are 25 -30%) compost to the soil. This means to add one quarter to one half bag of compost when planting and mix it with the existing soil. Compost holds water but it drains the soil. In summary, select the more cold tolerant aloe trees. Plant these on the east side of a landscape in the afternoon shade of a building. Plant them on a hill for drainage, add a small amount of compost to the soil when planting, plant wet and water periodically. Start small when using them and plant fewer in number.

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Newly Planted Landscape Tree Moving in Soil

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Q. I have a mesquite that I planted two years ago. It has grown rapidly, and I continue to move drip lines to the edge of its canopy. However, it apparently has “bundled” roots – roots that are quite loose when moving the plant from side to side. Are there any possible remedies, or do I just wait and hope the roots spread? A. I usually handle that type of problem when it is planted, not now. Sometimes a plant comes like that from the nursery and sometimes it arises from how it is planted. Plants that I buy with roots not spreading correctly, I return. Those kinds of plants should not be sold. Most nurseries don’t sell plants that “don’t have roots spreading out” (kinked roots) since the mid 1990’s. Nurseries now have a problem with growing some plants too close together and those plants “flopping over” when they are no longer staked. Most nurseries have a return policy. Some plants like that are discounted. Kinked roots often times relate to how many seasons of growth there are in the same container. They are bought with hopes that “bundled” (overgrown) roots will spread into the surrounding soil when planted in the ground in the soil correctly. They won’t. Stop wishing. Overgrown roots will continue to grow in circles and are permanently deformed. Nurseries are pretty good about removing or culling “root deformed plants” (plants not growing well) when they see them. Sometimes, when the roots of these plants are starting to get deformed, the root growth can be “straightened out” with some minor root surgery, spreading out the roots, realignment, etc. This type of root surgery may include some top pruning or heading back but seldom does. Top pruning depends on how much of the roots were removed. Consumers like “big plants”, the bigger the better. The thought is, “Increased money requires big plants”, rather than improved plant health. When I am planting, I always do two things; check the plant for stability after its planted and stake the plant to keep the roots from moving. Checking the plant for stability in the soil is making sure it was planted correctly. Secondly, plants are always staked, even if the stake is made from bamboo and comes with the container when it is bought. Usually it takes after planting (five gallon containers and smaller, depends on the size of the plant) is pushing the stake into the ground further and a small amount of green plastic nursery tape to keep the plant’s roots from moving. Staking keeps the roots stable and growing in the ground during gusting winds. Wind gusts can be unpredictable. That’s why I am constantly harping to “plant in wet soil”. Wet soils are “dirtier”, a “pain in the rear end”, and heavier, but they remove “air pockets”, fill gaps around roots, and stabilize plants in the soil. Plant wet whenever possible even when it is uncomfortable.

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White Grubs Feeding on Roots of Fruit Trees

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A “new” insect pest was found in the soil surrounding apricot trees at the privately owned Orchard at Ahern (entrance off of Clarkway Drive, near West Bonanza Road in Las Vegas, Nevada). It was new for fruit trees anyway. Some of you may know about it feeding on soil organics created by adding compost or decaying wood chip mulch to the soil. The insects in this group improve soil health by feeding from organic matter and recycling fallen fruit. Insects that feed on decaying organic matter are called Detritivores and include springtails, termites, ants, dung beetles, ground beetles and others. My feeling is that the young larvae come from a beetle. Those beetles that “eats” compost and gets some energy from it is suspect. Sometimes these “worms” (insect larvae mistaken for legless worms) “mistake” the small feeder roots of plants (living) with dead “organic matter”. Large numbers of these types of larvae feeding in the soil can cause damage to established fruit trees. How to know? Look for exit holes of adults at the base of any fruit trees. Those adults are gone. Adults mean they have “children” or larvae present in the compost or wood chip mulch. Any liquid insecticide will work if it comes in contact with this insect. But it must be in liquid form or made into a liquid to work. Use a soil drench if the label permits. Follow label directions.

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Prickly Pear Cactus also Called Nopal Cactus

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Q. I do not remember exactly how old this cactus is, but I think about 20 or so years! This cactus has not had this many flower buds! I will not wait for this plant to flower! Can you identify this cactus? A. That is Opuntia spp. This form of edible cactus (aka nopal cactus, bunny tails, beaver tails) has its origin in the dry parts of central America, mostly from central Mexico, but its distribution extends through the Americas. I grew edible selections of this cactus about 15 to 20 years ago when I gave up due freezing damage because of our Mojave Desert winter freezing winters. Lower parts of the Sonoran Desert are significantly warmer in the winter and hotter during the summer than lower parts of the Mojave Desert. They are also known as Nopal cactus because humans from central Mexico, after removing the spines (technically called glochids), would cut the succulent pads into strips. These “bite sized” strips are known in Spanish as nopalitos and the fruit (from the flowers) are called tunas. Some of the better selections (V1, F1 taken from lower elevations of the interior of Mexico) are quite versatile. These plants provide nopalitos, tunas (fruit naturally colored as red or yellow), and as a cattle supplement (fodder). The reason Opuntia has the spp. added to it is because there are many different varieties. F1 and V1 are the best selections of Opuntia spp. from the Sonoran Desert. The birds would devastate the best tasting fruits. Non-winter freezing parts of the Mojave Desert support Opuntia spp. as well, but research has not been done on nopal cacti from the Sonoran Desert, probably due to cultural differences.

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Thinning ‘Myer’ Lemon Tree

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Q. My Meyer lemon tree this year has hundreds of buds and flowers. Many on same branch or twig. Should I remove some of them, so I have fewer but larger lemons? A. No thinning of the flowers. The first thinning is done when fruit is about the size of your thumbnail. The second fruit removal is done about four weeks. Aim for about 30 to 40% fruit removal for mature citrus. In about 4 to 8 weeks, you should know where the leaves will be. That’s important for removing sun burned fruit. Remove misshaped, deformed, damaged, doubles or the smallest fruit during the first wave of thinning. On the second wave remove possible sunburned fruit and leave fruit that is or will be. shaded by some leaves. Fruit sunburning on exposed sides (usually west and south sides) and the tips is common in the desert. There is usually no sunburning on the east and north sides. There is a maximum size (determined by genetics) the fruit will reach but it is possible to maximize size in a higher percentage of fruit. Pinch the fruit between two fingers and gently twist it off. Pay close attention to the bottom of trees as a higher percentage of small fruit is located there. Young trees have fewer leaves to photosynthesize and will be better off in the long-term if they’re allowed to focus on their growth. You can leave a few fruit if you want a taste.

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