May 2024 – Xtremehorticulture

Root Depth of Newly Planted Trees

Leave a Comment / Uncategorized / xtremehorticulture

Q. I know you water a boxed tree to 24” deep but do you water a new tree to 24” deep even if is a sapling in a 15-gallon pot? A. What we have done with newly planted fruit trees (planted among established fruit trees) is move drip emitters closer to the trunk during the first year of establishment. These newly planted trees are irrigated 18 to 24 inches deep during this time, but the emitters are spaced on top of the rootball, close to the trunk. By fall, newly planted trees will become “established” and acclimated. The right number of drip emitters can be added for future growth at that time. The newly planted trees will become established when temperatures cool off by the fall months (usually by the end of September or early October). Planting during the spring months (late January through March) gives these plants time to get established by fall. Spring or early summer planted plants will usually get established by the following fall. Fall planting of trees and shrubs have a cool fall and the following spring to get established. Planting during the early summer months (April and May) will work but does not give them as many months to get established. Once plants get established (provided the planting hole was dug wide enough) during the fall months the water can be applied normally, with the other plants.

Root Depth of Newly Planted Trees Read More »

Eliminating Ants

Leave a Comment / Uncategorized / xtremehorticulture

Q. What is the best way to get ants out of my potted plants outside? A. The best chemical control method I have seen is a bait product made for several kinds of ants and manufactured by Amdro. I am sure other companies that make similar products are just as good. Ants take this bait back to the nest where it is fed to the queen as well as other ants. Control of ants is within 24 hours if done right. The usual reasons for failure are because the bait was not placed near the nest or because it became wet. If you use it, find the nest or opening to the ground. Place it near the nest in the ground. This product must be used dry so use it in containers when it is cool and after an irrigation. Read the directions for this bait and follow them precisely.

Eliminating Ants Read More »

Using Fire to Control Roots

Leave a Comment / Uncategorized / xtremehorticulture

Q. We are planting a 30-gallon apricot tree. The hole is large and deep, but the bottom has lots of thin roots from nearby trees. I took out most of the bigger ones. Can I torch these small ones? A. Roots no longer attached to the “mother” plant can be “torched”. Using fire to kill roots only kills the roots a few inches from the fire. Killing roots is due to the heat produced by the fire. During the summer, clear plastic can be used to kill roots during the day. All roots and diseases are killed at 180F in 30 minutes and allowed to “solarize”. That’s the temperature and length of time needed to sterilize dry soil 6 to 12 inches deep. If you are still not sure, then sever the roots from the tree with a sharp shovel. By the way, it is less of a problem if the planting hole is dug wider but not deeper. When digging a planting hole, it is recommended to dig the hole three times the width of the roots, but not any deeper than the roots or container unless, of course, there is a drainage problem. Water added to the dug hole should drain overnight.

Using Fire to Control Roots Read More »

Compost for Planting

Leave a Comment / Uncategorized / xtremehorticulture

Q. I bought straight compost. I told them I was going to use the compost for trees and shrubs planted outside. I hope this is the right product I need. I may be looking at other vines soon to cover some other cinder block wall areas. In this case I am thinking about vines that do not require a trellis. I looked at cat claws and read some reviews about how aggressive it can grow and how tough it is to control it in places like the southeast. What do you think about it for wall covers with no trellises in Las Vegas? A. Make sure whatever compost you use is mixed with sand at about one shovel full of compost to three shovels full of sand (25 to 30%). The planting mixture should still be dark, about the same color as straight compost. Straight compost may be too “hot” for plants that grow in soil and may injure them. The only thing municipal compost is in short supply is potassium, a macronutrient but high in nitrogen, phosphorus and lots of minor elements. Use Straight Compost as a Fertilizer You can also use straight compost as a fertilizer but be careful with it. Municipal compost can be “hot” (high in salts) so don’t put municipal compost closer than about 18 inches from the plants trunk or central growing point and then water it in. Soak the fertilized area with lots of water! Apply straight compost lightly. If you are not sure, then ask how to apply it when using it as a fertilizer. The soil should be close to the same texture as the surrounding soil but be darker and hold water better. You never want to use compost, straight, in a planting hole because it contains a higher level of different types of salt and is very different in its texture (water holding capacity, WHC). Cat Claw Vine A good choice is the cats claw vine for climbing on hot (south or west facing) walls. It is watered as a “mesic” vine or shrub. Cat claw vine is not a desert plant, but it does handle desert dry heat. It will not grab onto walls if the wall gets hot, above 145F. Those temperature and higher will be on hot-facing walls in full sun during the early and mid-summer months. During cool weather it will self-climb, but not on a hot wall. When the wall gets too hot, the new tendrils “burn” and the vine will stop climbing until cooler weather. The vine will reclimb again when temperature of the wall cools off in the fall. If you don’t over water it, it wont be a problem. It will easily cover the wall of a two story home if watered abundantly. Check with a local nursery for available choices of other desert vines. Have you tried using either paint or a texture (like cut reeds or cut bamboo) to cover the wall instead of vines? These additions to your landscape don’t use any water. Water use is important in the desert. Cut bamboo and reeds will need maintenance or replacement every few years.

Compost for Planting Read More »

Vines for Desert Landscapes?

Leave a Comment / Uncategorized / xtremehorticulture

Q. I recently planted two vines in my backyard; a Bank’s rose and a tangerine crossvine. I got the amended soil at Viragrow and the wood chip mulch at the demonstration orchard as you suggested. Shall I use wood chips mulch for both vines or not? How often shall I add the amended soil or fertilizer to the vines after having planted them? A. When in doubt, use wood chips as a surface mulch. Mulch of all types (including rock mulch) saves water and reduces weeding. Wood chip mulch, unlike rock mulch, “rots” into the soil and increases the organics of desert soil. Rock mulch doesn’t. After planting, apply this mulch in a circle six feet wide from the trunk and 3 inches deep. When the wood chips get sparse, freshen this layer with new wood chips. Keep them away from the trunk until the plant gets woody (five or six years after planting). The idea is to have the wood chips decompose or rot during the first few months and add “organics” to the soil. The wood chips will decompose in less than six months during warm and hot weather. When using a fertilizer, the type is not important but getting the nutrients it needs when its young, and applied to the right places, is important. After the hole is dug, apply a fertilizer high in phosphorus (something like a 16-20-0) at the bottom of the planting hole (a handful of fertilizer added to the soil at first when backfilling). A single application of fertilizer once a year in early spring is all the plant needs. After planting, use a landscape fertilizer no more than once when you see new growth. Neither vines are truly “desert” in origin. ‘Tangerine Beauty’ Crossvine The ‘Tangerine Beauty’ crossvine (Bignonia capreolata ‘Tangerine Beauty’) is a native, naturally climbing vine, found in the southeastern United States. It is found from Florida to Maryland and west to Texas. It is a vigorous vine with evergreen leaves and two-inch reddish, trumpet-shaped flowers. It can cling to structures like trellises, fences, arbors, and brick or rock walls. It blooms in the spring with repeat blooms throughout the growing season. It’s an early nectar source for butterflies and hummingbirds, and the flowers attract hummingbirds. Lady Banks Rose Unlike the crossvine, the lady banks rose flowers (yellow or white) only once in the late spring and is not a natural climber. Strong support must be provided. It grows to about 25 feet and is evergreen only in warm climates.

Vines for Desert Landscapes? Read More »

Planting a Lawn in the Desert

Leave a Comment / Uncategorized / xtremehorticulture

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).

Planting a Lawn in the Desert Read More »

Eastern Redbud is More Common

Leave a Comment / Uncategorized / xtremehorticulture

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.

Eastern Redbud is More Common Read More »

Water Needs of Tomatoes in the Desert

Leave a Comment / Uncategorized / xtremehorticulture

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.

Water Needs of Tomatoes in the Desert Read More »

Leave a Comment / Uncategorized / xtremehorticulture

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

Leave a Comment / Uncategorized / xtremehorticulture

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.

What Caterpillars to Control in March Read More »