Xtremehorticulture

Xtremehorticulture of the Desert

When to Fertilize Cacti

Leave a Comment / cactus, fertilizer /

Q. I have some cacti in my backyard.  Should I fertilize them and when? When cacti flower they need high phosphorus fertilizer. A rose or tomato fertilizer should work. A. The standard answer is to fertilize them lightly in the spring of each year. That is the standard answer. The purpose of fertilizer is to give the plants what they need or what is lacking in the soil. Once plants have what they need, stand back, and give them a chance to grow. Giving more fertilizer than they need, and watering plants more often, does not necessarily make them grow faster. Fertilizers are not a magic “on and off” switch; you can’t force plants to get larger and bigger by giving them more fertilizer than what they need. All plants have a genetic “maximum” at which they can grow. That is why most cacti grow slowly, and other plants may or may not, depending on their “genetics”. For cacti, it depends on the fertilizer level, watering and soil mix besides their “genetics”. There is one fertilizer exception and it is a bit tricky. Nitrogen fertilizers increase the speed at which any plant, including cacti, get larger but you must be careful. There is a danger from “growing too fast” for all plants including cacti. The fancy term is “luxury consumption”. To maximize growth, apply nitrogen fertilizers no more than twice during their growing season. Be judicious when watering them and don’t let the soil stay wet. But if your cacti are growing well without it, then don’t use it.

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Just Because Its a Cactus Doesn’t Mean it Loves it in the Mojave!

1 Comment / cactus, Mojave Desert /

             Some pictures of “torch” cacti in the yard of one of my readers. Great job! Several questions were sent to me regarding cacti. In general, the most common reason for failure of cactus is watering too often. The second most common reason for cactus problems is because it was put in a hot, bright location when it should be located in a protected part of the yard. The third reason is because the cactus was damaged during our winter cold temperatures and prefers being planted in a warmer climate. Argentine Giant Cactus (Not yet!) Automatic Irrigation             Be careful when putting cacti on an automatic water or irrigation timer. They are watered so infrequently that it sometimes makes sense to water these plants manually with a hose rather than automate it. When cacti begin to shrivel, it’s time to water. When they look plump and firm, they don’t need water.             If you’ve got lots of cacti and you are using an automatic timer, then run that station or valve when they need water but make sure they have good drainage if you water them automatically (without looking at them). A hose, manual timer and sprinkler also makes sense for larger desert plants. Watch for winter low temperature damage. Know your cactus! Water Cacti 12 inches deep             Medium-sized and small cacti should be watered about 12 inches deep. Large desert plants like a saguaro or Joshua tree should be watered 18 inches deep and have water applied to an area underneath them equal to at least half of their height. Watering a large area under large plants helps keep them stable and keeps them from falling over when the tops get large and heavy. Watering any of these plants too often can cause disease or unsightly growth problems. Cactus from the Sonoran Desert, like this nopal, may require warmer temperatures when planted in the Mojave. Your Cactus Has a Name             Find out the scientific name for your cactus and Google it. Learn where it originated from. Some cacti are native to the southeastern US or higher elevations in other countries. In these locations it was cooler so they will need protection from late afternoon sun in the Mojave Desert. Cacti native to our Southwestern deserts do not. They can handle hot and dry locations. Learn if your cactus should be planted in a gentler landscape location or can handle the harsh ones. Watering only at the base of most cacti results in blowover with wind and if they get tall like this one in Parker, AZ. Know Where it Comes From             Some cacti are tropical or subtropical and get damaged because of our low winter temperatures in the Mojave Desert. Cacti which can handle low temperatures of 20° F or lower probably will not need much winter protection in all but the coldest years. Other cacti which are less tolerant of these low temperatures might, depending on your landscape microclimate and location in the valley.

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My Husband Cut Down a Climbing Cactus!

3 Comments / cactus, climbing cactus, Columnar cacti, pruning /

Q. Look what my husband did? He cut my saguaro below the seams before consulting with me.  I know it looked kind of sick (the tree, not my husband), but he cut it. I am going to cut those chunks all the way down.  Cuts on climbing cactus like these may look bad but they are repairable A. From your pictures, I don’t think your cactus is a saguaro. I think it is one of the columnar cacti, also called a climbing cactus. Well, it is a setback for the plant because the cuts make it look ugly. The plant doesn’t care, but it is not pleasing to look at. New growth from just below the cut             If I’m right, and this is a climbing cactus, those cuts create new growth coming from the ribs just below the cut. The cuts will force new side growth, columns, that continue growing upward. Propagating columnar cactus             Another option is to remove all the damaged stems to a couple inches of the ground. Let them “sucker” and regrow below the cut. Remove damaged “arms” entirely if it looks bad. Cut these removed columns or “arms” into 12 inches long segments for planting. Put them in the shade for one to two weeks to heal the cuts before planting.             After two weeks, plant them in soil amended with compost (not upside down!) with about one third of the 12 inches stuck in the ground. Stake to hold them upright until they grow roots and they don’t fall over. Water every 2 to 3 weeks so that the soil is dry between irrigations.             Let the columns which weren’t cut continue to grow but “lean” against something upright. These cacti will get tall if they don’t freeze back during a very cold winter. Many of the columnar cacti are also called climbing cacti. They get so tall they can fall over if they don’t lean on something. Many of these cacti do not handle intense sunlight very well in the desert. In response to sunburn to the columns, these cacti will grow new site shoots and propagate themselves.             In your picture, some columns appeared to be damaged by intense sunlight. This damage was forcing a lot of new side growth from the columns. This cactus will grow much better with amended soil and put in a location where it gets some shade from the late afternoon sun. Now might be a good time to move it to a new location and let it “lean”.

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Control Cottony Masses on Cactus

Leave a Comment / cactus, cochineal scale, insect, white fluffy /

Q. I have small white nodules growing on my Indian cactus. Are they harmful? If so, how do I get rid of them?   Opuntia Or beaver tail cactus heavily infested with one of the cochineal scale insects. These insects can decimate cacti over time if left uncontrolled. A. I think you are talking about cochineal scale on the Opuntia or beaver tail cactus. This scale insect produces a white, fluffy mass on the pads on top of itself for protection. This insect is feeding underneath this white mass. Rubbing these white masses lightly with your finger, you find a royal purple color staining it. The insect beneath this cottony mass is dark red or purple. This is cochineal scale and makes a royal purple dye. Contrary to what some people have said, this is not the same cochineal scale the Spaniards sent back to Spain in the 1600s but a very close relative.             Depends on the cactus but they can devastate a cactus if not controlled.             First, control the ants. Ants pick up baby scale insects and transport them to pads that are underpopulated. These new pads are wide open pastures for scale insects to feed. Cochineal scale populate pads quickly. The ants harvest excrement from scale insects to feed their colony. This is a short video of a Weaver ant protecting another type of scale insect from its food supply. In this case, it’s my finger that is seen as a threat and the Weaver ant is protecting its horde aggressively. Video taken on our family farm in the Philippines.             Most ants are subterranean. One of the best methods I found to control ants is using a poison bait lightly sprinkled at the entrance to the colony. Usually these “ant holes” in the ground are easy to find but sometimes you must follow the ant trails to find them. (This doesnt work with Weaver ants because they don’t nest in the ground!)             I use an ant bait manufactured by Amdro. Follow label directions precisely. When applied correctly, it kills the entire colony, including the queen, in less than twenty-four hours. Borrowed a picture of the am drove container at Home Depot. Thanks to paulmirocha.com             Scale insects suck plant juices from the pads and build their populations quickly. Ants help them spread faster.             To remove white fluffy masses, spray the pads with a strong stream of water using a spray or sweep nozzle. This knocks the white fluffy covering off but doesn’t kill the insect hiding underneath it. They soon repopulate the pads. In summertime this could be weekly. In winter, perhaps monthly. Hosing off cochineal scale from the edible Opuntia cactus donated to the UNCE orchard by the University of Sonora – Hermosillo for demonstration trials. In the middle of summer, this had to be done weekly which none of the Master Gardeners like to do. If you don’t want to do it organically, which means frequently, then you’re faced with using conventional pesticides.              After spraying the pads with water, use organic or conventional insecticides to prevent scale insects, called crawlers, from repopulating the pads. Organic insecticides do not stay in the environment long so spray them more often than conventional insecticides. Neem oil varies in quality from different manufacturers. Unfortunately, there is not much quality control but if you find a good one, stay with it             Useful organic insecticides include Neem oil, soap sprays and other plant-based oils. Apply soaps and oils the day after spraying the pads. Reapply organic insecticides often. Organic insecticides I mentioned are total killers; they kill any insect sprayed so direct your sprays accordingly. Conventional systemic insecticides like this one works very well and requires fewer applications. But it is tougher on the environment.             Conventional insecticides last longer but are tougher on the environment. Useful conventional insecticides are systemic and applied to the “trunk” or soil. The poison moves into the pads from the point of application. Spray as soon as you see the cotton balls start to form.

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Fertilizers: Pay for Convenience or Do-It-Yourself?

Leave a Comment / acid loving plants, cactus, citrus, Fertilizers for cacti /

Q. What are the year-long fertilizer requirements for landscape plants ranging from acid loving to desert lovers such as cacti, palms and other plants to beautify home landscapes.   Many cactus lovers swear byproducts such as cactus juice but most cacti do quite well with a variety of different types of fertilizers A. Desert gardening and horticulture is more difficult to practice than traditional horticulture talked about on most blogs, information sheets, YouTube videos, books and other places. Most information in the media is derived from “traditional horticulture” and these practices may or may not work in the desert. This powdered fertilizer meant for dry or liquid applications has combined fertilizers that create more acidity than some other types. But it has other fertilizers in it as well good for acid loving plants.             When applying fertilizers to landscapes in desert climates and soils, consider soil improvement and irrigation beforehand. Soil improvement, where and when needed, solves many fertilizer issues. A good citrus fertilizer that can be mimicked by combining other fertilizers less expensive. But it’s convenience and knowledge that make the sale for most homeowners.             The biggest mistake made by desert horticulturists and gardeners is a lack of soil improvement to desert soils when and where needed. Desert soil improvement solves 90% of the fertilizer and irrigation issues in residential landscapes. Because the majority of plants grown in desert landscapes are NOT desert plants. Compost is a great all around fertilizer for most plants. It contains dozens of different minerals and elements not found in commercial fertilizers. Besides that, good compost is biologically active and help stimulate microorganisms better than commercial fertilizers.             Spend more money and effort on improving the soil than buying and applying specialty fertilizers. Improving the soil and using organic surface mulches around non-desert plants reduces the need for chemical soil amendments, fertilizer applications and pesticides. Called a starter fertilizer because it is high in phosphorus, the middle number. Excellent fertilizer when planting for the first time or seeding in the garden. You can mimic this fertilizer and save a little bit of money but is it worth it?             With proper soil improvement, here are my recommendations for fertilizer applications, either conventional or organic: ·        nitrogen and potassium is needed by all plants on a regular basis ·        apply phosphorous fertilizers when planting: seed, transplants from containers or bare root, rhizomes, bulbs or any plant just getting started ·        plants grown for their flowers or fruit require at least one fertilizer application of nitrogen plus phosphorus during the growing season and applied 2 weeks before flowering and fruiting ·        fertilize vegetables and annual flowers monthly; lawns every 8 weeks ·        fertilize prized landscape plants more often than “ordinary” landscape plants ·        use specialty fertilizers on rare occasions for very specific reasons

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Saguaro Leaning is Usually an Irrigation Problem

Leave a Comment / cactus, giant, irrigation, Las Vegas, Mohave Desert, Mojave Desert, nevada, planting /

Q. Our saguaro is about 10 years old.  In the last year or so four arms have popped out mostly on one side.  Now the saguaro is beginning to lean and we have propped it up. What do you suggest we do? Even though this picture is not from the submitter I wanted to post it for my friends who are viewing from other countries or part of the USA. Saguaro is not native to the Mojave Desert but to the Sonoran to our south. Even though they can be a bit sensitive to the Mojave winter cold they have done quite well in the lower elevations of southern Nevada. If people will stop putting burlap coats on it for the winter….. A. I would guess your irrigation is too close to the trunk. This concentrates the roots there and doesn’t allow root development further from the trunk for support.             In the wild, saguaros roots are about 30 inches deep near the trunk and spread a distance equal to its height at depths averaging only about 10 inches.  This matting of shallow roots spreading from the trunk is important in keeping the cactus erect.             I would prop it up as you are doing and immobilize the base so it cannot move. Then I would apply water at increasing distances from the trunk. These should be shallow and infrequent irrigations at distances from the trunk equal to at least half of its height.             You can do this by planting other desert plants that require similar types of irrigations in these areas. Water supplied to these plants will help to irrigate the saguaro. You can also do this by handwatering in these areas once a month with a spray nozzle.

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Saguaro Leaning and How to Correct It

7 Comments / cactus, staking saquaro, transplanting /

Q. I have a saguaro cactus with three big arms growing from it leaning toward the west. On the east is my house and shading the cactus from the morning sun. I also have been watering on the house side of the saguaro, the up slope side, and letting the water run downhill into the roots.  I water about 3 or 4 times a year and water very slowly. Do you have any suggestions about either stopping the continued leaning or how to straighten the cactus to upright?  Those two large saguaros have been in my yard for 17 years. Saguaro leaning due to shade from the house most likely A. These Sonoran desert monsters are top heavy. The root system of the saguaro is fairly shallow but expansive. This extensive but shallow root system can give this top-heavy cactus quite a bit of support under native desert conditions. But they have been known to blow over in high winds. These cacti, like most, are opportunists and take shallow water from the soil before it evaporates or taken by neighboring plants. Most of the roots away from the trunk can be found at depths less than 12 inches. Watering deeply around these plants is probably a waste of water. We put these plants in artificial desert landscapes and put them on drip emitters or run water close to the trunk. This can lead to a very small but dense root system close to the trunk. The roots don’t have to grow far from the trunk for water and so doesn’t help to stabilize the plant as the top gets bigger. Saguaro normally does not need to be staked when transplanted but here is one method that protects the trunk Your cactus could be leaning either because of the shade from the house or it might be leaning due to poor root support or both. If it is leaning and there is danger it will fall over then you will have to support it. In the meantime, we create a more expansive root system by placing enough other desert plants close to this plant so that the irrigations from these other plants can help the saguaro extend its root system further from the trunk. We could sprinkle irrigate the area around the saguaro, simulating desert rainfall. But sprinkler irrigation can lead to weed invasion in the landscape and weed control problems. From the pictures you sent, obviously your watering regime has given your saguaro some good growth but it sounds like the water is concentrated close to the trunk. I will post the pictures of your saguaro on my blog for others to see. Another possibility that could contribute to the leaning is how it was planted. If a hole was dug just large enough for the transplanted roots, and the soil was not conditioned properly, then this will encourage the plant to grow roots close to the trunk as well. All cacti grow better in amended soils than in straight desert soils or sand. Always amend soils for cacti at planting time. What can you do now? If the plant is leaning due to the house there is not much you can do. To give it better support put irrigation water at greater distances from the plant and use shallower irrigations. Like I said, giving saguaro deep watering is not going to help but getting its roots to grow wider might. If the soil is not loosened, it is best to loosen the soil surrounding the plant where you are watering to encourage growth at distances that will support top growth.

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White Fluffy Stuff on Cactus Can Be Removed Easily

Leave a Comment / cactus, cochineal scale, red dye, white fluffy /

Cochineal scale on Opuntia or beavertail cactus Q. My wife and I read your interesting article regarding white spots on cactus. Yes, we have them and didn’t know what to do about it. Now we do. I zapped the beavertail with a solid water stream and within seconds the spots were gone and the beavertail looked as good as ever. Many thanks for the simple solution to an otherwise difficult problem. Using a hose and sweep nozzle to wash off cochineal scale A.This is cochineal scale. A very similar cousin to this one was used for making a beautiful red dye. Remember that this does not get rid of them permanently. They will come back relatively soon and you will have to repeat spraying with your hose. If this becomes bothersome then you will have to rely on a pesticide such as Sevin after you hose them off. Make sure you read the pesticide label before applying it.

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