Xtremehorticulture

Xtremehorticulture of the Desert

Winter Cold and Chilling Hours May Not Be Cherry Problem

Leave a Comment / Cherry, chilling hours, flower, fruit /

Sweet cherry growing in North Las Vegas Nevada Q. I have a two-year-old pie cherry tree that needs so many days of cold weather to set fruit next year. Should I cover it with burlap for the winter? And if I do, then should I also cover the trunk or just the branches?   English Morello sour cherry in North Las Vegas Nevada A. How much protection you give it during the winter depends on where you live and your lowest temperatures during winter. Cherries are divided into two categories; sweet cherries and sour cherries. Sweet cherries are for eating fresh, out of hand. Sour cherries are considered “pie cherries” and used fresh or canned.             Sour cherries grow as far north as Michigan so I don’t think low temperatures are going to be a problem unless you live in northern climates. If you don’t live that far north, you don’t need to protect them through the winter. Bing cherry produced on sweet cherry tree in North Las Vegas Nevada. Don’t get excited. Twenty-five sweet cherry trees of six varieties produced twelve cherries in twelve years. Backyards in other locations in the Valley, sweet cherries were plentiful.             Chilling hours is the number of hours needed below 45°F to recognize winter is finished. When the number of chilling hours have been met, the plant waits for warm temperatures of spring so that it can begin flowering again.             Chilling hours are important but I think they are sometimes overestimated by growers and scientists. In the Las Vegas Valley, our chilling hours are estimated to be somewhere between 300 to 400 hours depending on winter temperatures.             I have grown five sour cherries in the Las Vegas climate and have had no problems with flowering even though many of them are rated between 400 to 500 hours. I have had problems getting fruit from the flowers. A lack of chilling does not appear to be a problem for sweet and sour cherries grown in Las Vegas.             I think the problem of setting fruit in the desert is more likely a humidity problem. Trees growing in backyard residences with pools or lawns set fruit each year in the Mojave Desert. Low humidity and failure to set fruit is a common problem with many tropical trees, with 30% relative humidity seeming to be the lower limit for successful fruit set.

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Oils Best for Controlling Scale on Bay Laurel

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Q. What is the best way to remove scale and aphids on Bay Laurel? A. Scale are insects have soft bodies and can crawl around from place to place when they are young. They are called “crawlers” at this stage in their life.             Once they find a place to live, they build a house covering itself called a “scale”. Underneath that scale the soft bodied insect is protected and sucking plant juices. Until it exits the scale to reproduce.             The scale covering on its outside protects it from predators as well as contact insecticides. Ants move crawlers to new locations just like they will aphids. The trick in controlling them is to catch scale insects in their “crawler” stage, when they are susceptible to just about anything including soap sprays.             The most effective sprays are considered spray oils; horticultural oils, supreme oil, dormant oil, a bunch of different names. Many of them are petroleum oils derived from paraffin or mineral oil.             It’s a good idea to apply these oils twice during the winter and again in the spring before or after flowering. There are sticky traps available that catch crawlers to identify when to spray. If traps are not used, repeat applications of spray oils during winter and spring is very effective.

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Borers in Italian Cypress and What to Do

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Q. Good day, Bob. I had 9 mature Italian Cyprus that have all died. Upon inspection by me, I discovered a borer in the trunks. I think it is the flat head borer. Other Italian Cyprus in my north Las Vegas neighborhood are dying as well. Have you heard of anything like this happening in the valley? And any preventive measures? Or is the insect destined to kill all the Italian Cyprus in the valley doomed the insect fate?   This was the picture sent to me several years ago when I asked for help identifying borers in Italian cypress. Flatheaded borer damage confirmed. A.  Years ago I thought borers was not a problem for Italian cypress. There are many reports from reputable organizations that many of our borers, flat headed apple tree borer and Pacific borer, are primarily attracted to trees damaged by intense sunlight or sunburn. I didn’t think this was a problem for Italian cypress so I thought that Italian cypress was not bothered by these insects. Plus the outside of the trunk is covered with evergreen foliage which should prevent egg laying on the trunks by these insects. Borers in Arizona cypress were well known as a problem. There were many reports of dieback in Italian cypress.   http://xtremehorticulture.blogspot.com/2013/10/q.html  http://xtremehorticulture.blogspot.com/2011/09/italian-cypress-browing-not-good-sign.html I asked for help from my readers because I wasn’t sure. A few years ago a reader sent me a picture of Italian cypress with damage suspected by flat headed borers. I am now convinced that flat headed board does occur in Italian cypress. Live and learn.    The active ingredient is Imidicloprid and a widely used insecticide for many crops. I has been implicated in honeybee colony collapse but has not been proven but has been banned in several countries primarily for this reason. Use of it as a soil drench for killing insects on nonflowering trees is perhaps a good use for it because it has a minimum impact on bees when used this way. The best protection is a soil applied liquid insecticide called a soil drench. One of the manufacturers of this insecticide is Bayer and it is called Tree and Shrub Insect control . Follow the label directions and the manufacturer claims up to twelve months protection with one application.

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Trunk Is Suckering Due To Damage

Leave a Comment / roots, Suckers, trunk /

Q. My tree is sending out shoots all around the trunk about one third of its height. Is there anything I should do to help the tree? Suckers coming from the base of the tree can mean damage higher up on the trunk. Some plants sucker more at the base than others. A. The tree has been “girdled” around the trunk and the trunk responded by suckering just below the damaged area.             Look closely at the trunk, just above the sprouts, you will see that the bark and “sapwood” have been removed all the way down to the dead inner core (wood). In other words, the tree trunk has been damaged beyond repair.             When both the xylem and phloem aka, sapwood, have been removed, the top of the tree usually dies quickly. It looks like this tree did not. This means the outer phloem has been removed but some of the xylem still remains. Suckers coming from the trunk due to trunk damage             The xylem is mostly responsible for transporting water up the tree to the leaves, through the trunk and stems, from the roots. The phloem, on the other hand, is mostly responsible for transporting sugars and starches from the leaves and stems downward toward the roots. Starches are stored in the trunk, roots and limbs. This tree appears to have been grafted with a sucker coming from below the graft.             With the loss of the phloem, the tree trunk beneath this damage will no longer get any of the benefits from the green leaves. However, with some of the xylem present, water from the roots is still pushed up towards the leaves keeping the top from dying.             If the tree does not die outright, it will die a slow death as the roots exhaust its food supply which can no longer be replenished.             The tree is a goner and should be removed unless you like to see it die a slow death. The suckers are responding to the damage to the trunk. It is trying to grow a new canopy because it knows that it cannot support the existing large canopy. You could regrow the top from the suckers but it will look funny for a long, long time.

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Coffee Grounds and Flower Beds

Leave a Comment / Coffee grounds, soil amendments /

Q. Is it a good idea to work coffee grounds into soil in flower beds? Does it help? A. Yes, coffee grounds are good. They add some, but not all, nutrients needed by plants and improve soil structure for better water drainage and air movement to the roots. This, in turn, improves plant growth.             Coffee grounds are better if composted first, but adding them “raw” is one step in helping improve the soil as well.             Don’t rely on coffee grounds alone. For instance, don’t go to your local Starbucks and add 100 lbs. of coffee grounds to a 4 x 8 planter or raised bed and call soil preparation done.             Adding only coffee grounds is like eating only corn and expecting to maintain a healthy diet. You need a variety of different foods to remain healthy. Your garden also needs a variety of healthy ingredients from different sources for plants to remain healthy.             A variety of minerals are needed by plants. Provide this variety by decomposing a wide variety of things in your garden soil besides coffee grounds.             A very good article was written by Sunset Magazine about the nutrients in coffee grounds.   https://www.sunset.com/garden/earth-friendly/starbucks-coffee-compost-test Probably the take-home lesson from this article about coffee grounds is about available nitrogen.             There is plenty of nitrogen in raw coffee grounds but this nitrogen isn’t yet released or available for plants. Releasing this nitrogen to plants is done through composting or letting it sit in the soil and “rot” or decompose. That’s what composting is. It’s “controlled rotting”.             Other things to add to flower beds in small quantities that round out available plant nutrients include wood ashes (not ash from coal or a petroleum sources), finely ground kitchen scraps (use a blender with a little bit of water to grind up kitchen scraps to a small size), shredded paper with black, not colored, ink, shredded cardboard, sawdust from wood but not particle board, leaves and grass clippings.             When added to garden soil, all these “rot” over time and release minerals and nutrients. But make sure they are pulverized. The smaller the pieces, the faster they “rot”.             Stop and think about it. Compost piles are mixtures of a wide variety of things but lumped together and managed so they “rot” faster. Finished compost makes a soil amendment with a wide variety of plant nutrients.             The nutrient almost always in short supply by plants is nitrogen. Animal manure is added compost because of its high nitrogen content. Vegans use green plant parts which provides exactly the same kind of nitrogen.

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Giant Figs Don’t Have To Come from Giant Fig Trees

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Q. I have Patrick Giant fig tree. Is it the same as Texas giant? If they are different, which one produces bigger fruits under the same conditions? A. I have never grown any of the so-called giant figs because they never interested me much. I focus more on the “taste” of the fruit rather than its size. I have grown about 15 to 20 different varieties in the Mojave Desert climate but none of them were marketed as “giant”.             I have harvested figs from fig trees that were quite large. I am quite certain this was from the “Briba” or first crop, not the main crop.             I believe the reason they were so large is because there were fewer fruit because of winter pruning. So, the fruit remaining got quite large. The fewer fruit on a tree, the larger fruit will become. The amount of “food” produced by a tree has more to do with the number of leaves, their size, and percentage of leaves in full sunlight.             My experience is that smaller fruit have more flavor than large fruit. And smaller fruit are usually more nutritious. This is because the minerals and nutrients in the fruit are more concentrated.             So large -sized fruit have never been particularly attractive to me. To me, large -sized fruit is more about “bragging rights” than flavor.

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How to Identify If Your Asparagus Plant Is a Girl or Boy

Leave a Comment / asparagus flower, asparagus fruit, Female asparagus, male asparagus /

Q. You mentioned that male asparagus plants produce more than female asparagus plants. How do you tell the difference?   This is what a female asparagus plant will produce. These are the berries that form from female flowers. You want to get rid of asparagus before these berries turn red. Once they are red, the seeds are mature and pulling them can disperse the seeds all through the garden. A. Male asparagus plants produce more spears than female asparagus plants because of the energy needed to produce seed by females. So male asparagus plants are preferred over female asparagus plants. You pay a premium price for “all male” asparagus crowns or roots. These are asparagus flowers that have not yet opened. They will be either male or female flowers. This will tell you if the plant is male or female.             We call plants that have male and female forms, “dioecious”. The plants and spears look identical. The flowers are slightly different. Male flowers and female flowers are easy to sex in some plants. Flowers of asparagus are not. Male and female asparagus flowers look nearly identical. This is a combination of immature asparagus fruits and flowers.             After harvesting asparagus spears for 8 to 10 weeks in the spring, the spears are allowed to grow into 5 to 6 foot tall “bushes” called “ferns”. These “ferns” produce small white flowers that are either male on the male plants or female on the female plants. The female plants produce round berries. The male plants do not. After you have finished harvesting asparagus spears in the spring, you let the remaining spears develop into full sized bushes like this called “ferns”.             The easiest way to tell the sex of it asparagus plant is to look for the “berries” that form from female flowers on the ferns. Dig up and remove the entire female plants including their underground crowns. Do this before these young green berries become red in color or mature and can spread seeds in the garden.             When you buy one or two-year-old asparagus crowns (roots) for planting, the more expensive ones will be labeled “all male”. To get all male plants, someone must “rogue out” or remove all the female plants including the crowns.

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Spray Oils Effective in Aphid Control

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Q. My 30 foot tall live oak tree is covered with aphids. Should you spray now or will the aphids die if the weather gets cold? Aphids on southern Live Oak A. Aphids overwinter at the base of trees and weeds nearby. Their populations are much smaller, but they are there. Eliminate weeds and apply “dormant oil” to the tree twice; once in December and again in January before new growth begins.             Dormant oil is a holdover name from decades ago when forms of this oil were safe to apply only during the winter. You might find this product now with names like horticultural oil, superior oil, supreme oil and others. Oil for spraying in a pint container. This company has chosen to call it a horticultural oil.             These newer oils are different. These are not vegetable oil or neem oil used as insecticides but a different type of oil that “smothers” overwintering bugs. I have used these newer oils in the fall, spring and even early summer months as long as the plants are not flowering. This oil for commercial use is in 2 1/2 gallon container. This company chose to call it Ultra Pure Oil             Ants and aphids rely on each other. Controlling ants helps control the spread of aphids and keeps them in check. Controlling ants when aphids are problems is an important component when controlling aphids. I like to use ant bait products like Amdro applied exactly as the label says. One of the ant baits supplied by Amdro             Don’t worry about small numbers of aphids on trees if you eliminated weeds and controlled their ant buddies. Leave them alone unless there is some problem you can’t live with. If the ant problem is intolerable, apply soap sprays, neem oil or a systemic insecticide if it’s a bad problem. But don’t go in that direction unless you must.

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When to Repot Lime and Lemon in Containers

Leave a Comment / Container citrus, container lemon container line, pots /

Q. We have a Meyer lemon and Bearss lime in clay pots. The pots are deteriorating and the trees should be replanted into other pots. In the desert, what time of year is best to transplant these trees into new containers? A. Put fruit trees into new pots in late Winter or the beginning of Spring. In our Las Vegas climate, this would be from mid-January until sometime in February. Bearss lime is sensitive to mild freezing temperatures. Myers lemon tolerates cold temperatures better. Myers lemon grown in northern Afghanistan in protected houses for commercial sale             If they are kept outside, wait until the coldest weather of winter has passed before repotting them. Plants growing in containers or pots need their soil “refreshed”, or the plant repotted, every 3 to 4 years to prevent a slow decline in health.             Replanting or repotting is not difficult if the containers and plants are relatively small; the plant is gently eased from the container, roots and soil around the edge of the root ball is shaved off, and the plant placed back into the container with fresh soil or container mix surrounding the rootball.             If plants are large, the soil still needs to be refreshed every few years. Perhaps one way is to auger vertical holes throughout the rootball, while still in the container, and backfill these holes with new soil mix.             Auguring holes into the rootball damages plant roots but the old container soil must be refreshed. Another method is removing the root ball from the container, removing old soil with a strong stream of water, pruning some of the roots and repotting it.             Prune the top back when finished to compensate for any root damage during repotting.

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How to Harvest Butternut Squash

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Butternut squash fully mature and ready to harvest Q. When do you harvest butternut squash? A. Butternut squash, a winter squash, should be fully mature before it is harvested. Knowing when to harvest comes from experience.             Look at the color of the squash fruit and the condition of the vine. Squash fruit should be tan, brown or orange brown depending on the variety and the vine at the point of connection to the fruit should look like it’s dying.             In early winter, another way is to let the vine die from a light freeze and cut the vine from the squash fruit. A common method talked about is to press a thumbnail into the “skin”. When mature, the skin should be difficult to scratch or puncture. This is a rather subjective method and I don’t like it much.             I don’t particularly like this method because it can puncture the outer skin. This puncture or wound is a possible entry point for rotting microorganisms if squash fruits are stored for any length of time. All fruits and vegetables should be handled carefully without creating damage.             Don’t pull squash fruits from the vine because the wound left when the vine separates from the fruit damages the outer skin and leaves an open wound, unless you’re going to cook or process it right away.              Cut the vine from the squash fruit, leaving about ½ inch of vine attached. They store better at garage temperatures than house temperatures.

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