Xtremehorticulture

Xtremehorticulture of the Desert

Grass Removal Mandates and Landscape Water Use

Leave a Comment / grass removal, large trees irrigation, pine trees, roots /

Q. Because we are an HOA, we are mandated to remove the grass surrounding our condos.  We have over 100 mature trees. What is the best irrigation to put on these trees after the grass is removed?  We want to save as many trees as possible. My particular unit had the grass removed many years ago and I have a large pine tree.  It is irrigated with drip emitters surrounding the tree about 4 feet from the trunk.  It is doing fine. There are lots of reasons why large pine trees do well when the lawn is removed and drip irrigation is installed. Notice shrubs irrigated nearby. They need water as well and may be feeding the tree water. A. Yes, lawns are big water users. Some types of grass (tall fescue in particular) needs daily watering during the summer and use about 7 feet of water (7 x 12 = 84 inches of water) each year to look good and lush. Bermudagrass lawns use less; about 4 and a half feet of water (54 inches) each year. Less, but still not low enough. We want to get our total landscape water use averaging around two feet of water each year. It makes sense that lawns are targeted because of their higher water use. Newly planted Chinese pistache in a lawn. The roots of this tree will grow more shallow to accommodate the frequent lawn watering and other shallow rooted plants growing at its base. t is not only HOAs. Any entity that has property is required to conserve water by removing lawns.  I would also include trees too large for the area and “out of scale” with the home. Just substituting lower water use plants, and finding a lower water use irrigation system alone, does not work. You will lose some trees, particularly the large ones. Pine trees with adequate water will be full and the limbs will be growing strong. Do you want to choose where water is applied or have someone decide for you? Lowering total landscape water use requires finding a balance between open areas that need no irrigation with areas that require irrigation. Total landscape water use is finding a suitable balance between the two. A less complicated reduction in total water use is finding a balance where water it is needed and where it is not. Growth of pine trees comes from the ends, terminal buds. The new growth should be, in older pine trees, average about 10 to 12 inches. Your landscape committee should be charged with identifying zero water use areas. Filling these areas may include the use of statuary, murals, paintings, gazebos, etc. They don’t need water. Start by identifying areas where loss of plants is not as important as other places. As these places eliminate the need for water, substitute statuaries, murals, paintings or gazebos that need no water but still beautify. Landscape art (no water) should draw your attention. It can substitute for a lack of plants that need water. Landscape art can be an investment.  Next, shade the south and west sides of buildings to prevent overheating of these units during the summer. Use deciduous trees for solar heating during the winter. Consider removing large plants on the north and east sides of buildings that have little function in heating or cooling the home. If plants remain or you find other plants, concentrate on smaller plants (less than 20 feet tall for single story homes) that use less water. Water the remaining trees and shrubs in irrigation “clusters” for ease of water delivery and finding leaks. Even though it may be considered a desert tree, if it’s not needed or the size is too large for the spot, get rid of it of make is smaller to save water.             Water savings come from the “averaging” of water use over the property and the creation of non-irrigated “open” spaces. You can have your cake and eat it to but not everywhere! These open spaces instead may use statuaries, murals, paintings and gazebos that don’t use water. This west side of a hospital in Parker, Arizona, shaded the windows and walls with low water use trees that don’t get all that big. The rest of the landscape uses minimal water.

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Where to Get Free Woodchips in Las Vegas?

Leave a Comment / bark chips, free, mulch, wood chips, Woodchips /

Q. In one of your previous articles you mentioned free woodchips. Where do you go to get them? Woodchips are different from bark chips. Bark chips are prettier, but they float and blow away in moderate wind. Woodchips don’t do that. They don’t easily blow away (I have personally seen them withstand 70 mph gusts) or float. Woodchips should be applied at least 2 – 3 inches deep to control weeds and conserve water. Woodchips rot into the soil (where its wet) and improve it by increasing its organic matter content. A. You have to travel to North Las Vegas, but you can get a pick up load or trash bag full from the University Orchard. Call 702-257-5555 and get an update from the Master Gardeners regarding woodchip availability and what days and hours to get them. Woodchips are usually available on Tuesdays, Thursdays and Saturdays in the mornings (except holidays). Woodchips are usually available in North Las Vegas (in the Aliante area) about 100 yards east of North Decatur and Horse Drive at the Center for Urban Water Conservation. Bark chips or bark mulch floats in water and blows in the wind. It resists soil rotting. It is inferior to woodchips (chopped up) from the entire tree.              Woodchips are different from bark chips. Bark chips blow in the wind, resist soil decay and are water proof. Woodchips are made from grinding the entire tree so it can be taken to the dump. Yes, it includes bark woodchips but it is a smaller percentage of the chips and it is mixed together. Woodchips includes ALL of the tree ground up into woodchips, not just the bark.  The weed in the picture is perennial nightshade and, along with bermudagrass, will grow through the woodchip mulch. Why? Because they are perennial and push through two inch mulch. Most weeds controlled by a surface mulch like woodchips are annual weeds. Most first weeds are are annuals.              Bark woodchips are pretty. They make a prettier looking surface mulch. If you want your surface mulch to look pretty, then use a bark mulch. Or use both separated in layers.  Bark chip (bark mulch) doesn’t rot as easily as woodchips because the bark is made to be weather resistant.             Tree woodchips are not as pretty but functional. When laid on top of the soil in a layer at least two inches thick it saves water, controls most weeds and improves the soil. This is what can happen if mulch is not used. Annual and perennial weeds have a field day growing. No competition for sunlight, air and water! Weeds have a field day.             Organics in our desert soil is severely lacking. To rot woodchip mulch takes water. Water and organics in the soil are linked. More water applied, more organics in the soil. Most trees and lawns require at least 2% organics in the soil. Vegetables need more, usually closer to 8% for quality vegetables.  Map of the US soil organic matter content (scientists call it soil carbon content) https://extension.umn.edu/soil-management-and-health/soil-organic-matter-cropping-systems How to judge if your soil has organics in it? Use the color first. If your soil is very low in organics it will be closer to light brown or even tan in color. If organics are present, desert soils become darker and start develop some structure. The higher the ‘organic content” in the soil, the darker its color. If a soil has 2% organics in it, it has a color similar coffee with a creamer in it. If it has 8% organics, it is a “chocolate brown” in color. Mojave desert landscape soil in Las Vegas, Nevada Visually is how to judge if organics should be applied to Mojave desert soils or not. In most Mojave desert soils, we judge a soils “organic content” from its darker color. That’s because it starts off light tan in color. If your soil has a darker color and you can make “dirt bombs”, then adding organics such as woodchips won’t help much when planting trees and shrubs. But that organic content may not be suitable for growing quality vegetables without compost added. A method to use to judge soil organic content is the color of the soil. This is a jar test of a desert soil.

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Vegetable Seed Use and Storage

Leave a Comment / planting, seed, storage, vegetables /

Q. I have some old vegetable seed that I planted. I was told I wasted my money and time. Do you think I did? Vegetable seed storage for longevity depends on which seed or cuttings depending on the vegetables but maintaining an appropriate temperature and low humidity are important. A. It depends on the seed, how it was stored and how old it was. Usually, large seed doesn’t store as long as smaller seed; maybe two or three years. Small seed might store for 5 or 6 years or longer.             The best temperature and humidity to store seed totals less than 100. That is directly from the National Seed Storage Lab in Ft. Collins, Co. For instance, if the temperature that they were stored totaled about 70F, then the humidity should be less than 30%. If the humidity was 70%, then the temperature needs to average around 30F. Of course the best temperature and humidity for seed storage is close to freezing for temperate seed. Having them both total less than 100 is suitable for a couple of years.             When using old seed, plant two and expect one to live is a good motto.             When storing seed, I try to keep the temperature and humidity of vegetable seed as low as possible. I stay away from buying seed exposed to heat or direct sunlight. I use a desiccant (corn starch works okay), put them in a glass jar with a screw lid, and put them in the fridge. They will keep this way for several to many years depending on the oil content of the seed. Small seed (e.g., tomato, eggplant, beet, carrot) usually has less oil in it than larger seed (e.g., beans, corn).

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Grape Bunch Diseases are Now Here

Leave a Comment / botrytis, bunch disease, downy, grape, mildew, powdery /

Q. I am a big fan of your (Las Vegas Review Journal newspaper) column, but I haven’t seen any answers about what’s happening to my grapes. Please advise. This the stuff isn’t on all my grapes. I have four plants and maybe 10-15% have this white stuff on certain bunches. This is what are called collectively, “bunch diseases”. But are usually either Botrytis or powdery mildew. A. I thought this might happen mostly because of our wet spring. Bayer tells us, when treating for grape bunch diseases, that about half of the improvement is due to better air circulation and the other half using a copper-based fungicide. They are right! Collectively, both botrytis and powdery mildew are called “bunch diseases”. Warning. Grapes must be present on the label because of testing and recommendations concerning the rate of application. Sometimes, months after we see the disease during wet weather, the bunch disease shows up as dried berries. Too late to do much about it now.             This looks like one of the grape diseases, probably grape botrytis or downy mildew. Try removing bunches and leaves so that you have one bunch every foot. If it is tight with leaves, remove some of the leaves as well. Don’t remove too many leaves so that you get direct sunlight on the grapes or limbs. You want to improve the air circulation around the bunches and the berries but without putting the bunches (and limbs) in direct strong sunlight for any length of time. In severe cases, the grape bunch may just dry up!             You can apply a spray mixture of a copper-based fungicide according to the label. Copper sulfate, Liqui-Cop, and Bordeaux sprays come to mind, but any copper-based fungicide should work. You may have to repeat the application. Read the label. Remember fungicides help stop plant diseases but do not “cure” the plant of a particular disease. You are spraying to prevent the spread of grape botrytis and powdery mildew. There is some evidence that Neem oil has given some protection, but copper-based fungicides are better. One of the copper-based fungicides. Any fungicide that contains copper in it is considered a “copper-based” fungicide. https://www.gardeningknowhow.com/garden-how-to/info/what-is-copper-fungicide.htm             You may be too late with this application, but it is worth a try. Do it very soon and follow label directions for controlling these “bunch diseases” on grapes.

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Pruning Shrubs Correctly

Leave a Comment / hand pruners, pruning, renewal pruning, summer /

Q. Attached you will see my 25-year-old bottle brush bush. As you can see, it needs some attention. Can I shape it a bit by trimming it back without harming it? The only trimming I have done is clipping off brown ends each spring (none this year) caused by winter cold. It displays beautiful color for several weeks when the weather warms up. 25 year old Bottle brush shrub A. Yes but be careful and don’t let the landscape maintenance clods ruin the plant by shearing it with a hedge shears. You may want to consider separation between branches or removing offending branches altogether. It requires either cutting the plant to the ground OR selectively removing some of the older stems. Whether it produces suckers or not will tell you which way to prune it. Either way requires deep pruning cuts, not using a hedge shears.            Never use a hedge shears unless you want to replace the shrub in a few years. Hedge shears are for pruning a hedge. That’s why the tool used is called a “hedge shears”! If it flowers in the spring, then prune it immediately after it finishes flowering so it has time to grow and produce wood for new flowers. Formal hedges require quite a bit of work and time. Because they are formal, attention needs to be spent on them once a month. Anything growing “out of place” is cut back with a hedges shears. https://www.hedgesonline.co.uk/formal-hedging An informal hedge accomplishes the same thing but with far less work. https://laidbackgardener.blog/2016/06/29/a-hedge-for-laidback-gardeners/             In your case, use a hand pruners and snip three or four branches from each side of the plant, deep inside it, and select where to open it up. Hide your pruning cuts at least 12 to 18 inches inside your shrub. Reach deep inside your shrub. There are several places to prune. Move your hand to each crotch. Ask yourself, “If I were to remove that stem, how would it look?”            Because it’s so dense on all sides, “cut at a crotch” and remove an entire offending branch or stem. Concentrate on removing stems or branches that are growing down or up. From each section of the shrub remove a stem so the remaining branches are more open and can “breathe”. Remove no more than about ¼ of the branches every three years or so. It will not need more than that. Pruning with a hedge shears may look okay when the shrub is young, but as it gets older the shrubs older wood needs to be removed. This requires a few well-placed cuts deep inside the shrub.             When you are finished pruning, the shrub it should look like it was never pruned. That’s the mark of a good pruning job. Who wants to look at an ugly shrub until it grows back? Also spring is the time to apply an iron fertilizer/chelate to the soil to cure the yellowing that occurs on this plant.

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Winter/Spring Flowering Plants to Attract Bees

Leave a Comment / honeybees, mustard, rock, rosemary, texas ranger, water, yellowbells /

Q. I’ve been trying to attract bees to my garden and thinking about a hive at some point. Need to put in some year-round flowering plants first. Rosemary comes to mind. Any thoughts or literature that comes to mind. Rosemary flowers during the winter and spring when honeybees are active and looking for open flowers. A. Rosemary is a good choice; it flowers during the winter and is lower in water use since it is a Mediterranean plant that is smaller. Any plant that has conspicuous flowers during early spring and is cold hardy will work. That is one reason roses work so well. Other plants to consider that flower during that time and are cold hardy for our climate include the different Texas sage and Tecoma types. Tecoma stans and Texas ranger also flower during the winter or spring. Don’t forget a mixture of annuals and perennials that have brightly colored flowers. Use many different colored flowers like mustards, clovers, desert bluebells and blue eyes, and the like. Scratch the seed into the soil with a rake and start watering them twice a month in December and January with 15 minutes of water from a sprinkler. Turn off the water when your fruit starts flowering. Flowering mustards, many are winter annuals that flower during the late winter. Don’t forget water. Honeybees like to haul water during the winter as the hive starts to warm up. Bird baths and plastic troughs dug in the ground help attract bees and other critters. Don’t let the bees drown. Put rocks in the water so bees have a place to land. Honeybees are active during the daylight anytime temperatures are in the mid-50s, clear and sunny and little to no wind. Night flowering plants such as some cacti don’t work because bees need to see the sun to fly. Honeybees are supplemented with sugar water when they can’t find flowers they like. Feeding the colony with sugar water helps to keep the population alive during the coldest parts of winter. Honeybees like to haul water in the summer to cool the hive. Give them a chance by putting some stones in the water and give them clean water to use.

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Tropical Plants for the Mojave Desert

Leave a Comment / citrus cold protection, legs, winter cold /

Q. Besides freezer damage, what other differences do tropical plants have from non-tropical plants? Our farm in the Philippines and champeduk, a tropical fruit similar to durian and jackfruit. A. Tropical plants freeze sooner, which just means they start getting injured at temperatures below 55F. Tropical plants and fruit experience damage starting much higher temperatures than temperate plants (plants that can tolerate freezing temperatures). Temperate plants experience freezing injury starting at 32F. Damage to bananas (soft and brown) occur at higher temperatures; a few hours after putting them in the refrigerator (39F). Not even a freezer! Even tomato fruit are damaged when put into a refrigerator. Most tropical plants and their fruit are damaged at storage temperatures higher than temperate plants (apples, peaches, strawberries, pomegranate, ash, poplar, mulberry). A banana, locally produced in Las Vegas.             Much of this type of damage occurs because plants don’t have “legs”. Plants, more than animals (which can move from place to place because of “legs”) are more sensitive to changes in their environment. They can’t move! Plant damage due to freezing is the most obvious. But other environmental changes are also important such as the strength of sunlight, wind, water availability and quality, air, and soil changes. Plants don’t like it. They are damaged or dead. Animals don’t like it. They move. Coconut palms near our farm in the Philippines. We have several coconut palms at our farm including a “dwarf” form.             The better we can provide for these damaging environments (garage protection from cold, west side vs east side of buildings due to light intensity, protection from wind, change in humidity, irrigation and drainage), then the plants are better off. Citrus freeze protection in Las Vegas.

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Starting a Raised Bed…Again

Leave a Comment / compost, irrigation, raised bed, sidewall /

Q. I want to start up my raised vegetable bed again after two or three years. Can you help? A. Raised beds can be simple or complicated. It’s what you want or like. Raised beds can be made out of cement block or wood. 1. Mix compost into the soil first. You can use “steer manure” but it should be done in the fall so it has time to “rot”. Remove your irrigation and mix a layer of compost into the soil as deep as possible. If the soil is ten inches deep in your raised bed, then mix the compost that deep. The soil should be similar from top to bottom to improve drainage. Raised beds can have side walls or not. Make side walls out of 45 degree sloping soil. Add compost once a year. How much to mix into the soil depends on how much is there. You might mix a 1/4-inch layer each year in a well amended soil. Or you might mix to as much as one fourth of its content, and then one annual quarter inch layer after that, if it is raw desert soil. You can judge how much is present by digging with a hand trowel or check it visually using its color. For vegetables the soil should be easy to dig with a trowel when it is moist and dark. Adding compost to raised beds without side walls. Add water to settle the soil. Raised bed made from lumber. Next is how much fertilizer to add. That depends on how “rich” the compost was. Some animal-manured composts are rich, while others are not. Most soils are darker after composting and ready to plant “as is”. Some need a “starter fertilizer” added. Again, ask your salespeople. Fertilizer is added just when plants start growing. Finally, is the “when and how much” to water. Get the soil wet from top to bottom. Add at least a quart to the soil or about 30 minutes of water. Irrigation is trial by error. but once you have it established, watering seldom changes. If you are using Las Vegas tap water, then water until the entire soil mix is wet from top to bottom. Watering like that flushes salts in the water out of the soil. This takes around 30 minutes, but it might be more or less depending on your soil and irrigation system. How often to water depends on the time of year.  Water is filtered and pressure reduced. Hopefully there is a way to shut off the water when needed. In the summer, water once before it gets hot. That is usually once a day. Watering only once when it gets hot allows for the roots to get water from top to bottom. If you are using well water, hopefully there is a way to flush the irrigation lines of debris and bacterial growth. This is done in the opposite end from the incoming water. There is a trend to water as often as nine times a day! Water only once! If you are using drip irrigation it will be added slowly. Be careful. Frequent irrigations (more than once or at the most twice per day) encourages lots of surface roots and loss of heat tolerance because shallow roots is where the water and dissolved fertilizers are located. Plants with lots of surface roots are not very tolerant of the heat. Instead use a light application of mulch and irrigate once, during the heat and in the morning. You want your vegetables with water when they enter the heat of the day. Irrigation can be on a raised bed without sidewalls. The vegetables need water at least once a day to grow in the summer. Preferably at the beginning of a hot day!

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Plant Roots and Water Follow the 40-30-20-10 Rule

Leave a Comment / divide, fourths, plant roots, quartiles /

Q. Please explain the 40-30-20-10 rule when watering. Why is it important? There are lots of different ways to water plants. Doesnt matter how deep the roots are, all roots generally use water following the 40-30-20-10 rule. Divide the roots into four equal parts. The top fourth of the roots uses 40% of the water, the second quarter uses 30%, 20% and 10% follow suit. Drawing citation lost. A. Most plants use water stored in the soil following the 40-30-20-10 rule. Divide the roots of plants into four equal parts. If it is a large tree and its roots are three feet deep, divide this three feet into four equal parts (nine inches for each part). If one-foot-tall plant roots are one foot deep, divide the roots into four equal parts (3 inches for each part). After a heavy rain or a full irrigation, plant roots start using the water stored in the top quarter (25%) first. When this top layer starts getting used, then the plant begins using the second (25 to 50%) layer of stored water, then the third and finally the fourth. When the plant finishes using water stored in the soil, it uses this water following a 40% (top)-30%-20%-10% (bottom) rule. Plant roots, just like the top, grow when they use water. This is one reason plant roots grow deeper when they are watered deeper.

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Use Weather App on Your Phone

Leave a Comment / phone, weather app, Weather prediction /

Q. Why use a weather app? I have planted tomatoes at the same time every year and they have done well. Weather app for Henderson, Nevada A. You were lucky. Sometimes warm season plants like tomatoes, peppers and eggplant are planted as early as mid-February. Other times the weather stays cold until mid-March. Using a weather app on your phone helps predict the weather two or three weeks ahead.             Warm season crops like tomatoes prefer growing in warmer air and soil temperatures than winter or cool season crops. Having two raised beds, one in full sun and one in seasonal shade, can add about one month to your growing season. But there are other tricks you can use as well. Look at your phone’s weather app. Covering the prepared soil with clear plastic a week before the weather starts to warm up helps get an early jump on warm crops like tomatoes.

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