Xtremehorticulture

Xtremehorticulture of the Desert

Desert Green Conference for Landscape Professionals Nov 6-7

Leave a Comment / Desert green conference 2014, desert horticulture, where can my professional landscaper learn more about desert horticulture /

Desert green conference for professionals will be held on November 6-7 at the Henderson Convention Center. Tell your gardeners about it and encourage them to attend. There are many good presentations made to help local gardeners become better at their profession. Click here for more information about the Desert Green Conference and Regisrtation Click here to see the conference agenda and Registration

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Chinese Pistache Leaves Curling

Leave a Comment / Chinese pistache disease problems, Chinese pistache insect problems, how to irrigate Chinese pistache /

Q. I have a Chinese pistache tree which is nice and green but the leaves began to curl. I spoke to someone at the nursery where I bought it, I did what they said but I am not seeing any change yet. Can you help me save my tree that cost me so very much money when I had them plant it last year? A. Chinese pistache is a tree that does very nicely in our desert climate with very few problems. One thing that it hates is a soil that stays wet. Curling leaves on pistachio can be an indicator of a water or insect problem. Once the leaves are curled however, these leaves will not straighten out again. However new leaves that come out should be normal if you have corrected the problem. Curled leaves can indicate water stress; not enough water in the soil or watered applied to often. If watered too often, curled leaves can be an indicator of root rot or trunk rot at the soil level which is called collar rot which results if the soil is kept constantly wet or it is buried too deep. Whatever you do, be sure not to water this tree daily! You will kill it if you do. You are far better off giving it more water than it needs, but applying less often. The amount of water to apply depends on its size. How often you applied the water depends on the time of year. In midsummer you should not be watering more often than three times a week. For desert adapted trees like this one you should be able to get by on one, or at the most, two watering’s in one week. I wish I could tell you how many minutes of water to apply but water does not work in minutes, it works in gallons. If your tree is watered by drip irrigation, you should have four drip emitters around the tree. Once the tree is above 10 feet, you should be adding more emitters around the tree. The emitters should be no closer than about 18 inches from the trunk. If the problem is from insects feeding on the leaves and causing them to curl, a systemic insecticide intended to be applied to the soil above the roots should kill the insects. The leaves that are curled will stay curled. You will not see normal leaves until you see new growth. 

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Eggplant Beautiful Bush No Fruit

Leave a Comment / problems with eggplant in the desert, To grow in the desert, went to fertilize eggplant, why does my eggplant not produce fruit /

Q. I have grown plants in whiskey barrels every year with a good harvest. This year my eggplants have grown bigger than ever, beautiful, look healthy and have lots of purple flowers but almost no fruit. Since planting it’s just been one giant flower bush. Why is it not producing fruit? A. I am guessing it is a combination of probably three things; variety, weather conditions and general care. Stick to varieties of eggplant that have done well for you in the past. Don’t just buy any eggplant off the shelf and expect the same results. Varieties are important. Purple Thai eggplant, a good variety for the Mojave desert if you like Asian style eggplant Secondly is the weather. At very high temperatures many vegetables will fail to set fruit. This is because the pollen may become sterile at high temperatures and the fruit will start to develop and fall off. Some varieties are better at setting fruit at high temperatures than others. Thirdly is soil enrichment and fertilizing. If your soil has been amended with a good quality compost prior to planting then I would not fertilize with any nitrogen fertilizer until I saw fruit developed that was a couple of inches long. Eggplant forming fruit in July If the soil is enriched heavily with good compost and then we fertilize the plants with high nitrogen fertilizers we can end up with wonderful vegetable bushes with little to no fruit. I would suggest you mulch the plants as well. This will help keep soil moisture more constant. If soil moisture goes up and down during the day, the plant may drop flowers or fruit as well. Less likely is a lack of bee activity. I am guessing your bee activity has been about the same as previous years so that it is not likely to be the problem.

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Azalea Problems in the Desert

Leave a Comment / Can I grow azaleas in the desert, what is causing my azaleas to have brown leaves, what is causing my azaleas to turn Brown /

Q. We have an azalea planted on the northeast side of the house.  At this time of year it gets no sun. The tips of its leaves are brown.  What needs to be done? A. Azalea is a very difficult plant to grow in our climate and soils. It likes soils on the acidic side, with lots of organic matter in the soil, absolutely hates salts and salinity, does not handle direct sunlight very well at all in the desert, in short it is one of the more difficult plants to grow here. That being said, I also planted one about 30 years ago in a very similar exposure. It did the same thing as yours and that is the leaf tips turned brown or died after about three years. If you are going to try and make this work to any degree at all your exposure would be okay but you have to modify your soil with lots of good compost, finally ground sulfur or aluminum sulfate to help lower the pH of the soil and wood mulch. Make sure you have enough water surrounding the plant so that the soil doesn’t dry out. If this were my plant I would push any salts out of the soil surrounding the roots by letting the hose slowly run water around the base of the plant for several hours so it is completely drenched. I would wait two or three days and do it again. The purpose of this is to push out any salts that may have accumulated around the roots. I would check to make sure that there are enough drip emitters, if that’s what you’re using, to thoroughly wet the soil around the plant every time it irrigates. If not, I would add some. Next I would lightly dig in around the base of the plant some good compost mixed with finely granulated sulfur and some iron chelate. Next I would look for a specialty fertilizer for azaleas and fertilize the plant lightly this fall. If this were a water-soluble fertilizer I would mix it in a bucket of water and pour around the base of the plant. I would repeat the fertilizer application in the spring. Finally I would cover the soil under the plant with a couple of inches of wood chip mulch. The old believes that have scorched tips will remain on the plant until you get some new growth and they finally drop off. Read another point of view about azaleas in the desert

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Wormy Artichokes a New Problem?

Leave a Comment / Armyworm in artichoke, Caterpillars in artichoke, controlling insects in, how do I control, IPM, loopers in artichoke, worms in artichoke /

Q. What is the worm or caterpillar that attacks artichoke plants and how do I control them?  I had a beautiful artichoke plant last year and had four or five great artichokes from it right away. Then the worms (caterpillars) struck and were all through the artichokes. I cut it down and it came back beautifully but now the worms or caterpillars are eating all of the leaves. A. This is most likely either damage from armyworms or loopers. I am guessing that it is probably armyworm. It doesn’t matter which one, the control measures are the same just the timing could be different. The usual time we see damage from armyworms is either in the spring of the fall. They can attack the leaves or the flower buds. Loopers crawl along like the cartoons of caterpillars where the midsection “loops” up in a curve. Armyworms don’t. Spinosad as a liquid that can be attached to a hose for an application. You would use either a spray of Dipel, Thuricide or Spinosad. All three of these sprays are considered organic and do a very good job on these types of critters. Their death is not immediate but they do stop feeding a very short time after these sprays come in contact with them. They will die a couple of days later. BT in the form of Dipel as a dry, flowable insecticide. This one must be mixed in water and constantly stirred or agitated to keep it suspended. If you see them now, spray. Mark your calendar for next year and spray when you first start to see damage. You can apply a preventive using your calendar as a guide when to apply. Bt in liquid form These sprays are good to have around since they can be used to control a number of different “wormy” pests on tomatoes, peppers, eggplant, grapevines, fruit trees, petunias and many other plants. Read more about pest management in artichoke

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Fall Or Winter Head Cold or Allergies? Shoestring Acacia.

Leave a Comment / acacia stenophylla, allergies, desert landscape, pollen, tree selection /

Shoestring Acacia is in bloom right now and has been credited with allergy problems. In fact, they will bloom through most of the winter. Shoestring Acacia flowers in Bloom in January Shoestring Acacia can grow up to 40 feet tall quite rapidly and it is relatively upright so it can be useful in more narrow locations and in scale with two-story homes and commercial buildings.They are good selection for desert landscapes but allergies might be a problem.   Shoestring Acacia with a fairly wide form. It is propagated from seed so there is a lot of genetic variability which means you can have narrow ones and you can have wider ones. If you are picking one that is intended for a narrow area, pick one that has a narrow habit to begin with in the nursery. Chances are if it is narrow in the container it is more likely to be narrow when it is older. If you pick one that is not so narrow when it is small, you do run the chance of having a fairly wide Shoestring Acacia.   Shoestring Acacia, narrow form. This tree is started from seed so there is a lot of variation in the trees. Pick one that is narrow to begin with and hopefully it will stay narrow if that is what you want. If you want one that’s wide, then pick a form that’s wide in the nursery. It hails from Australia which, like so many trees from Australia, blooms during the fall or winter months rather than spring and summer. It is popular here in the desert Southwest and some people consider that it might be over planted.  There are complaints from people that it is messy and the leaves, because they are long and narrow, are difficult to clean up. Whatever you do, don’t cut the top off. Trees that are pruned like this are ruined for life. Shoestring Acacia topped at commercial planting North Decatur and CC 215

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Can Sago Palm Grow in the Hot Desert?

Leave a Comment / cycad, growing cycad in the hot desert, growing sago palm in the hot desert, sago palm, will it grow /

Q. I understood that sago palms liked afternoon shade.  Can this plant handle afternoon sun with reflected heat and rock mulch? Sago palm or cycad in planter in desert landscape A. Sago palm or cycads will perform better with less care if they are planted in eastern or northern exposures rather than southern or western exposures. They will survive in your spot but will not look their best. They will grow in full sun and under some very tough desert conditions if the soil is improved, they are receiving the right kind of irrigation and fertilizer and surrounded by wood mulch.  Sago palm growing in partial shade in the desert When grown under these very harsh conditions they usually grow shorter fronds, the fronds are frequently discolored with a yellowish or bronze appearance and the fronds may even scorch or burn at the tips. When these plants are grown in more protective environments they look much better with more succulent growth, longer fronds, darker green with a lot less care. It would be incorrect to say they will not grow under some very harsh conditions but they will perform better and with less management in less hostile environments. Will it survive with rock mulch in an intense desert environment? Sometimes. But it will not have a long life expectancy and not look as pretty. Under rock mulch conditions with very little soil improvement I would give them 5 to 10 years looking okay after they were planted. 

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What is Causing the Webbing in My Desert Willow

2 Comments / desert willow has tents, hornworm, sphinx moth, web caterpillar, web tents, what is causing webbing in my desert willow /

Q. My desert willows in Kingman, Arizona, are being eaten up by worms. The web-like pods are all over the branches, but I have not found anything inside. I certainly do not want to spray as the trees are over one of my gardens and close to some windows. A. I did some quick checking but could not find this critter mentioned anywhere. How do you k now they were being eaten up? It is possible they have done their damage and now have moved on leaving their webbing behind. Sphinx moth found dead on sidewalk in May in Las Vegas. Desert willow is used in butterfly gardens but it is usually for the adult butterfly rather than the immature larva (worms) or caterpillar. If they are causing a great deal of damage then they should be controlled. Tent caterpillar webbing Worms or caterpillars that do cause damage to desert willow are the Sphinx moth larva or “worm” and relatives of tent caterpillars. The larva of the Sphinx moth is gigantic with the horn coming off of its rear end. You would’ve recognized that one if you had seen it. Sphinx moth to give you perspective on size of the moth. Bt formulation from Monterey The other caterpillar is much smaller, along the sizes you’re talking about, but they usually form a webbing one or 2 feet across and they feed inside this webbing or tent. That’s why they call these “tent caterpillars”. Tent caterpillars reproduce quickly and do a lot of feeding over a short period of time. My guess is that these critters will not last very long and be on their way for the season. The desert willow will respond and survive. But in the meantime that tree will have some damage. You could use a spray of BT, called usually either Dipel or Thuricide which is an organic control. It will only target “worms” that become moths or butterflies. Also Spinosad will work as well. This way you could avoid more poisonous conventional sprays.

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