Xtremehorticulture

Xtremehorticulture of the Desert

Desert plants: Jojoba

Leave a Comment / Desert landscape plants, desert plants, selection, Simmondsia chinensis /

JOJOBA Andrea Meckley, Certified Horticulturist [email protected] Description:  Evergreen shrub Mature size: 6 feet tall x 6 feet wide Water use:  low Exposure:  all day sun Origin: Sonoran Desert Uses:  Hedge, screen, or foundation plant Hardy:  to 15 degrees F Despite its scientific name Simmondsia chinensis, jojoba does not originate in China.  The botanist Johann Link originally named the species Buxus chinensis after misreading a collection label “Calif” as “China”.  This hardy shrub has leathery grey-green egg shaped leaves and the female plant produces edible nut-like fruit.  Jojoba provides year-round food for many animals, including deer, javelina, bighorn sheep, and livestock. The nuts are eaten by squirrels, rabbits, other rodents, and larger birds. Only Bailey’s Pocket Mouse, however, is known to be able to digest the wax found inside the jojoba nut.  The name “jojoba” originated from the O’odham people from the Sonoran Desert who treated burns with an antioxidant salve made from a paste of the jojoba nut.   In large quantities, the seed meal is toxic to many mammals, and the indigestible wax acts as a laxative in humans. Jojoba nuts contain more than 40 percent “oil,” which is actually a liquid wax. The wax is highly resistant to oxidation and is stable at high temperatures. These properties make it a very high quality lubricant, equal to sperm whale oil. Only sperm whale or jojoba oil is acceptable for some industrial applications. The wax is also used in cosmetics. For these reasons and because sperm whales are endangered, jojoba is being developed as a commercial crop in several countries.

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Leaves of Crepe Myrtle Yellowing

Leave a Comment / crepe myrtle, soil organic matter, Watering crape Myrtle /

Q. The leaves of my crepe myrtle are turning yellow some show signs I think of a specific mold on underside of the leaves. Please advise in your usual expert advice. A. When yellowing occurs at the tips first it usually indicates a salt problem. This is possibly due to a lack of water or not enough water applied during an irrigation. It is also possible water is not delivered often enough so the soil becomes too dry between waterings. It is also possible it might be watering too often and not letting the soil dry between waterings. Crape Myrtle growing at the research center with wood mulch, annual applications of complete fertilizer, iron EDDHA and foliar application of Miracle Gro Look closely at your watering habits. If you are watering by drip make sure you put lots of gallons down every time you water. For trees this is gallons of water applied each time. The number of gallons depends on the size of the tree. As the tree gets bigger it needs more water applied at each irrigation. NOT watered more often. Make sure when you water that it is not daily or even every other day. This time of year every three days is adequate but put enough gallons down, not a small amount. Estimate how much water is delivered each time you water. You can use the chart below if you do not know the gph (gallons per hour) of your drip emitters. For instance if your drip emitter delivers 10 ml of water in 9 seconds then you have a 1 gph emitter. Increasing the total water applied will flush salts from the tree. Number of seconds to deliver gph (3600 seconds/hr) (3785ml/gal, approx. 4000) Gph     10ml     20 ml    30ml    40ml     50ml    60ml    70ml    80ml    90ml    100ml ¼           36 sec. 72           –           –            –           –           –           –          –            – ½           18       36        54         72 1            9         18        27         36           45       54         63         72 2            4.5       9         13.5      18           22.5 3            3          6           9         12           15 4            2.25     4.5        6.75     9            11 5             – 6             – 7             – 8             – 9 10           –            –            –           –           4.5      5.4         6.3       7.6        8.1       9.0 If you suspect you are watering too often then increase the number of emitters (this way you do not need to increase the minutes). Increasing the minutes means everything else will get more (or too much) water. If you suspect you are not giving enough water each time then flush the soil with water several times to remove excess salts and rewet the rootzone deeply. Put a hose at the base of the tree and let the hose run very slowly around the tree near the emitters for several hours. Or build a donut around the tree and fill it several times a few days apart. Or buy a small inexpensive sprinkler that goes on the end of the hose and let it run for 15 to 20 minutes. Repeat every other day three or four times to flush salts. This could also be from a lack of organic matter in the soil IF the tree is surrounded by rock mulch. Buy some decent compost and apply it to the rocks under the tree and water it in thoroughly. Do this two or three times this fall and repeat it in the spring.

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Plum Tree Murdered by Borers

Leave a Comment / Santa Rosa plum sap, what is causing sap to come from my plum tree, what is the cause of sap oozing /

Q. I have murdered my 5 year old Santa Rosa plum. The borers have finished it. I treated the tree for iron twice earlier in the spring, and It never seemed to help, I now see why. They are in every branch, and looks like the main trunk. I had white washed as you suggested, but I should have reapplied every year, since it faded some, and of course the tree grew. I have learned a valuable lesson, and I feel terrible for the loss of my tree. Thank god, I had a bumper crop last year, hopefully I have enough jam to hold me a few years until a new tree takes shape. Thank you so much for years of tips and tricks for our garden. Santa Rosa plum ripe A. So many borers as you stated is an indicator that perhaps the branches were getting overly heated and burned by the sun. Always keep a full canopy to shade the limbs and trunk. Pruning fruit trees in the desert is an art. It is finding a fine balance between removing enough and removing too much wood from a tree. Sap oozing from cut limb on plum. Sap oozes freely from damaged limbs on plum. This is a defense mechanism and when working properly drowns any infesting insect with sap. Never prune so much that it opens up the canopy for sunburn to the limbs. Mulch the soil which helps keep a full canopy and dig out borers as you see them causing sap oozing from the trunk or have limb dieback. I will do this in the winter time when all the leaves are gone and it is easy to find damaged limbs.

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Selecting Crabapples for the Desert

1 Comment / Crabapple selection for the desert /

Q. I am hoping to plant two semi -Dwarf Crabapple trees on the west side of my house. Could you please tell me which cultivars will do well here? I am looking for crabapples that are good for raw eating, jelly, and apple butter. I also need to know which are good for cross pollinating each other.  Also, does our local nursery stock these in the fall and spring for planting, or will I need to order them off line? A. I don’t like the idea of putting a crab apple in a Western exposure in our hot desert environment. You run a very big risk of sunburn on the limbs and borer infestations due to the sunburn. I have never done any trials with crabapple here so Information is limited. I did contact Tom Spellman at Dave Wilson Nursery in California and he confirmed that Dolgo has done well under desert conditions and the fruit has performed well under our conditions. It is an old variety with good fruit and is self-fruitful so you don’t need a pollinator.  dolgo crabapple from Dave Wilson nursery Dolgo crabapple is a good pollinator for crabs that need pollinators. I would start with this one. There are some crabs at Gilcrease but I don’t think they know the variety. It is very possible that some or all are Dolgo. Try to choose varieties that have fruit which mature during cooler times of the year for best flavor.

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Texas Sage Outgrowing Its Space after Two Years

Leave a Comment / Pruning Texas Ranger, texas ranger, Texas sage, Using hedge shears for pruning /

Q. We have three Texas Sage bushes that are about two years old and doing very well – so well in fact that they are outgrowing their area. I have seen these plants where they have been trimmed back and they look very good. Is it okay to do this without harming them, and if so, should I wait until they go dormant? A. Regarding your Texas Sage, there are varieties that are smaller than others. Perhaps it might have been better to select one of the Texas Sage which are smaller to begin with so you wouldn’t be faced with this so early in its life.  Texas Sage or Texas Ranger can be pruned with a hedge shears but really should only be sheared this way if they are intended to be in a hedge. If you intend to use a hedge shears on these plants expect them last about five years before they get really woody at the base and don’t have much foliage anymore.  Larger Texas sage pruned with a hedge shears This may not work for you if these plants are placed into a location where you need to keep them small. But the best way to pruned them is by removing two or three of the largest stems at the soil level. The idea is to continue to remove the oldest wood from the base of the plant every couple of years.  This keeps the plant juvenile and doesn’t interfere with its flowering. Hedge sharing is usually done when there has been new growth which results in removal of the flowers before you can enjoy them.

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Vinca Yellowing and Growth Is Stretching

Leave a Comment / leggy, stretching, vinca groundcover, Vinca lack of light, yellowing leaves of vinca /

Q. Our Vincas are in pots and have done very well all summer. We have noticed they are starting to be tall/ spindly, and the leaves are beginning to turn yellow. They have been watered three times per week with an auto irrigation system, supplemented occasionally with Miracle Grow from a watering can. Is it the end of the growing season for them, or is there cure? If you don’t know what Vinca looks like A. The usual problems with Vinca are soil related problems, not enough light and watering too often or the soil not draining well. Vinca likes to grow in a soil that is well amended down to a depth of about 8 to 12 inches, in full sun and fertilized with a high nitrogen fertilizer once a month. If they are in full sun then your soil is probably running out of organic amendment and you are losing pore spaces in the soil. The addition of compost to the soil at planting time down to a depth of at least 8 inches is necessary at the time of planting. If you don’t add enough compost to the soil, the soil spaces that are created by the compost and soil mix begin to collapse. As these pore spaces collapse, less aeration reaches the roots and water no longer drains through the soil like it used to. There is not much you can do about that now. It really has to be added at the time of planting. The soil will continue to collapse more and more and then you will start to see isolated plants die. Upon close examination these plans will have died from root disease or collar rot which is a rotting that occurs right at the soil surface. The other possibilities are lack of light reaching the plants and not fertilizing them on a regular monthly schedule. You have nothing to lose so try adding a complete fertilizer like Miracle Gro or Peters and see if they perk up. That will not, however, cure a problem if there is not enough sunlight.

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