Xtremehorticulture

Shade Plant Selection for the Desert

Q. My garden has matured and now I have flower beds that are shaded.  What plants grow in the shade here and where can I buy them? A. I hesitate in answering plant selection questions sometimes because I do not know what the nurseries are carrying as well as I might. It can be a problem for me to recommend plants and then you go and find out they are not available. The recommendation is not a problem so much as whether you can find it anywhere. Frequently plant recommendations become circular, going back and forth with both of us frustrated. Shade is different for different plants. Shade for vegetables is light to very light shade, no more than 30 to 40%. In even light shade, some plants like okra produces beautiful foliage and flowers but produces no fruit. Going over 40% shade will oftentimes result in no production of fruits like tomatoes for instance. While leafy green vegetables can handle more shade than flowering or fruit-producing types. This translates over to ornamental plants as well. Generally speaking for shady spots stay away from plants that produce flowers. Flowering plants normally require more light than nonflowering plants. In the old days of Las Vegas we would see a lot of ivies; Boston, Needlepoint, Algerian, etc. They were tough and did well in the shade and water was plentiful. Water is more expensive than it used to be and landscapes are much drier now. My best advice is to send you to the nursery and ask for some recommendations. If you have the time, get five or more recommendations and then I can run down the pluses and minuses of each. A2. Response from Andrea Meckley ([email protected]) Here are a few flowering plants I have found that work in the shade: ·       Lily Turf ·       Ajuga ·       Vinca minor (Periwinkle)-aggressive ground cover ·       Begonias (annual) ·       Kalancohe (annual) I also use plants with colorful foliage in shade for color: ·       Nandinas ·       Coleus (annual) ·       Aucuba japonica Andrea Meckley, CH Horticultural Consultant and ASHS Certified Horticulturist

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Why I Hate To Answer the Question,”What Plant Should I Use for….”

I send these types of questions now to Andrea Meckley. She LOVES these kinds of questions. So thank her for answers to your question, “What plant should I use for….. Your “which plant should I use” is now answered by a Certified Horticulturist. A list of plants for specific purposes is fairly easy to compile and readily available on the internet. The problem I have is giving recommendations to homeowners, they go to the nursery, the nursery doesn’t have the plants, they come back to me, I send more examples, they find it at the nursery and don’t like it or the nursery person doesn’t recommend it, they come back to me…etc. This is the reason I usually send people to the nursery and tell them to come back to me with five plants they find at the nursery and then I go through and tell them the pluses and minuses of each. This is why I hate recommending plants in a blog. You are faced with availability problems and the likes and dislikes of a homeowner. It is not like making a pesticide or fertilizer recommendation.

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Any Fruit Trees That Don’t Need Pesticides?

Q. Are there any fruit, nut, fig, or olive trees that I can grow in North Las Vegas without using pesticides? A. Very few fruit trees require pesticides as a general rule. Most of the fruit at the orchard is grown without pesticides. I talk about them because they sometimes do occur. You will still get good production from apricots, peaches, plums, apples, pears, almonds, pistachios, pomegranates and figs. There are occasionally pests that do get in all of them.

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Cathedral Oak a Good Choice But May Be Hard to Find

Q. A few days ago we saw a cathedral oak at the Springs Preserve.  It was identified as “Quercus virginiana ‘Cathedral’”on its little sign.  Does it do well in Las Vegas?   Do its leaves fall at all (like pine needles drop)?  How tall/wide does it get in our area?  Is it a fast grower?  Any other facts? A. From Andrea Meckley. Below is some information about Quercus virginiana ‘Cathedral’.  I did contact Pete Duncombe at the Springs Preserve and his comment was   “they are performing very well”.  I have not seen any locally available and the nursery Pete got them from is now out of business.  This plant is listed on the Southern Nevada Regional Planning Coalition Plant List as a semi-evergreen, maturing about 40′ x 40′, requiring moderate to high water use. USDA hardiness zones for this plant are  7B through 10B covering Las Vegas at USDA zone 9a.  Personally I think it is a possibility, however because of the availability and water usage, I would go with one that Bob suggested, Holly oak. From:  www.sptreefarm.com The Cathedral Live Oak tree is a Quercus virginiana or Southern Live Oak and it is a cultivar (Quercus virg. ‘SDLN’ pp12015) meaning it is cloned from a mother tree with the same DNA to copy the dense and upward structure of the tree.  Properly pruned, the Cathedral Live Oak Tree will not sprawl as wide as a Standard Live Oak Tree. The Cathedral does grow as tall  and is considered a happy medium between the narrower Highrise Live Oak and a typical Standard Live Oak. Holly Oak (Quercus ilex) matures around 30′ high x 20′ wide.  An evergreen, medium water user, that has a slow to medium growth rate depending on soil and water conditions.  It forms a round head with dark green leaves covered with hairs beneath and seasonal acorns.  I have seen them available at local nurseries (Star and Plant world).   If you don’t see them, they can be special ordered.   I hope this info helps and you enjoy your new town of Las Vegas. Andrea Meckley, CH [email protected] Horticultural Consultant and ASHS Certified Horticulturist

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Poor Canopy Development in Newly Planted Large Tree Could Be Lack of Water

Q. I think I this might be a pink locust tree. I’m seeing a lot of dead branches. The tree was planted last Fall. Should I give it some fertilizer to help it push out new growth? A. The tree looks a little skimpy on the foliage side but I don’t see anything from this distance that gives me much overall concern. Check to make sure it was not planted too deep. Some landscapers are notorious for digging a hole barely large enough for the root ball. This can also be part of the problem. I tell people now if they buy a large tree from a nursery, hire some people and dig the hole before they deliver the tree and buy good amendment for the backfill while they are at it. A thin canopy like that can also mean a lack of water. The lack of water would be on the quantity applied at each irrigation, not on the frequency of irrigation. Right now that trees should get by easily receiving water twice a week. But I would guess a tree that size would require the same amount of water as about half of the box that it came in. So if that was a 24 inch box I would guess it would need 20 to 30 gallons each time it was irrigated. Apply some good fertilizer and take a hose and soak it after you made sure it was not planted too deep. Do that about once a week for the next month and see what happens.   Sunburn on locust followed by death of that side of the tree. When the bark was pulled off, borers damage was seen. If this is an Idaho or Black locust like Purple Robe, they are very susceptible to sun damage to the trunk. Once the trunk gets damaged they frequently are attacked by borers. As a precaution it might be a good idea to give it a soil drench with Merit insecticide as a precaution. The same insecticide can be found in Ferti-lome’s tree and shrub systemic insect drench. I know Viragrow has a pretty good price on it if they still have the small containers.  If at all possible you want that tree to develop lower scaffold limbs to help shade the trunk.The canopy could use some light pruning. Remove crossed branches or branches growing on top of each other or too close together. You can do that now if you don’t remove too much or wait until this winter.

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Is Grub Guard Safe to Use in my Landscape?

Q. I ran across an item called Grub Guard in the catalog. It contains beneficial nematodes. Would these be the same kind of nematodes that attacked my tomatoes last year?  A. These are entirely different nematodes. These are good guys and pose no problems to other plants. The ones that attacked your tomatoes are probably root knot nematodes which are never good, always bad guys. You are safe to use beneficial nematodes in your landscape.

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My Pomegranate Has Those Little Red Bugs

Q. I have a pomegranate tree planted by birds about 20 years ago. I never had bug problems on this tree before 2011. In 2012 it produced about 150 pounds of pomegranates. In 2013 the tree did not produce any fruit at all. This year the tree is loaded again but it is infested with those little red bugs that I think will turn into those ugly creatures you have been talking about. We don’t want to use poisons. Have there been any new developments for control? A. This particular bug, the leaf footed plant bug, is a growing problem for Las Vegas gardeners. The only way you will have a good crop of pomegranates, and most likely pistachios, is to spray. Leaffooted plant bug on pomegranate             The two choices you have are to spray with a conventional insecticide, which you call a poison, or spray with some sort of “organic” spray which I guess you might call non-poisonous.             Conventional insecticides leave a longer residual on the plant so you do not have to spray as often. Most organic sprays must be repeated more often because they don’t have much of a residual or none at all.             One of the most effective “organic” sprays is soap. You can make your own soap sprays but for most people I would highly recommend buying insecticidal soap already made. The soap used to make insecticidal soaps is less damaging to plants than grabbing scented Ivory liquid and using that. Safers insecticidal soap             Insecticidal soaps, to be effective, must be sprayed directly on the insect. They have no residual. When these bugs die from the soap, new ones will come in and invade their territory so you have to re-spray frequently.             The most effective time to spray soaps is toward dusk when bugs have settled in for the night. Soap sprays are not selective. They will kill any insect that comes in direct contact with your spray, good or bad.             Organic sprays containing pyrethrum, an insecticide derived from either Dalmatian or Persian chrysanthemums, will probably work well. However, pyrethrum is a poison. Use it carefully and wear protective clothing. Pyrethrum farmer in Kenya             Synthetic or manufactured sprays that chemically resemble pyrethrum, which you would categorize as a poison, are probably going to be effective as well. Scientists “tweaked” the chemistry of pyrethrum to give it more “knockdown power” and last a little longer. These are called synthetic pyrethroids.             Chemical names in the ingredients will say things like “Permethrin” or “pyrethroid”. These chemicals emulate natural pyrethrins but are manufactured and as such are not “organic”. If you decide to go conventional, then look for these names in the ingredients. Make sure the label permits you to apply it to fruit trees.

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New Texas Ranger Not Looking Good After Daily Watering

Q. I planted a Texas Ranger shrub three weeks ago in some sandy and rocky soil. I have been watering it with about two gallons daily. I added one inch-deep bark mulch in a 1 foot circle around the plant. Now I am finding yellow, brittle leaves on the lower stems and curling leaves on top. Am I overwatering? A. Yes, it is definitely watered too often. Overwatering can be in two forms; giving too much water OR giving water too often or both at the same time. “Giving too much water” relates to the number of gallons you give a plant each time you water. “Watering too often” relates to how many times in a week you give water to a plant. Texas ranger hedge sheared and consequently the flowers removed             It is far more damaging if plants are watered too often rather than given too much in a single watering. Rangers do fine without wood mulch. They will benefit from it but they don’t really need it like other plants, such as roses and many fruit trees in the rose family, do.             Now, a second problem. If wood mulch is in contact with young tender stems of plants, it can contribute to a disease called collar rot. Collar rot basically rots the trunk of the plant in contact with continuously wet mulch just above the soil surface. Collar rot of bean but the principles are the same.             A third problem is just plain old root rot. This happens below ground and not at the soil surface. Root rot happens because the roots cannot “breathe” due to a lack of oxygen. The open spaces in the soil are continuously filled with water. Basically the roots “drown”.             Bottom line; pull the mulch away from the trunk about a foot or eliminate it. Make sure the plant is planted at the correct depth in the soil. Make a basin around the plant about 2 feet in diameter and fill this basin with water from a hose or bucket.             Set your drip emitters for twice a week during the summer. On the same days your drip emitters come on, fill the basin with water. This helps settle the soil around the root system.             When you see new growth, eliminate the watering in the basin. Use only the drip emitters from that point forward. Use enough emitters to deliver 1 to 2 gallons each time you water. Next year, add one more emitter but leave the number of minutes unchanged.             Fertilize once in January. Do not use a hedge shears to prune unless you intend it to be a hedge. If the plant is intended to stand alone, use selective pruning and remove one or two of the largest stems near the base of the plant every two to three years. A. Yes, it is definitely watered too much. Overwatering can be in two forms; given too much water OR giving water too often. It is far more damaging to plants to water them too often. Rangers do fine without wood mulch. They will benefit from it but don’t really need it. If wood mulch is in contact with young tender trunks or stems of plants, it can contribute to a disease called collar rot. This disease is in the soil and can spread into healthy tissue if the plant is stressed. The other concern is just plain old root rot. This happens because the roots cannot “breathe” due to a lack of oxygen to the roots. Basically the roots “drown”. Plant parts without light need oxygen. Plant parts that are green and exposed to light need carbon dioxide AND oxygen. Keeping the soil moist and having the wood mulch in contact with the trunk is a double whammy on this plant. If the soil is amended at the time of planting (University of Arizona discourages that) then you should water only about twice a week right now. We are in nearly the same climate zone. Bottom line….i hope it is not too late but pull the mulch away from the trunk about a foot or eliminate it. Make sure the plant is planted at the correct depth in the soil. Make a basin around the plant for the first few weeks and, in addition to your drip irrigation, water with a hose twice a week in the basin two feet in diameter surrounding the plant. This helps eliminate air pockets and settles the soil around plant roots. Actually you should be adding water to the planting hole when you are backfilling the hole with amended soil so the soil and water (mud) can flow around the plant roots. When you do this you will see air bubbles coming from the soil as the excess air is eliminated from the planting hole and around the roots. When finished planting, the plant should be solidly established in the hole. When you move the plant, it should not wiggle around in the soil. When you see new growth in a couple of weeks, eliminate the watering from the hose and go to emitters. Use enough emitters to give you 1-2  gallons each time you water. Next year, add another emitter. Fertilize once in January. Do not use a hedge shears to prune it but let it grow with little pruning.

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Tomatoes With Black Bottoms Now Being Seen

Those of you who were lucky enough to get your tomatoes planted the first part of March have already tasted your home grown tomatoes. Quite a few of you have discovered tomatoes with black bottoms. What do you do?             This problem, called blossom end rot, is seen every year here on tomatoes and sometimes peppers and eggplant. No one really knows the exact cause for this physiological “disease” but scientists agree it probably comes from mineral imbalances inside the fruit. The mineral usually associated with blossom end rot is a lack of calcium. Blossom end rot of tomato             On the East coast, in acidic soils, the recommendation is to “lime” the soils or add calcium carbonate to the soil so the plant does not “run out” of calcium. But calcium sprays applied to tomatoes do not cure the problem. Blossom end rot of pepper, frequently confused with sunscald             This is odd because calcium sprays such as calcium chloride applied to the fruit of apple and pear trees cure their calcium deficiencies, namely “bitter pit” and “corky spot”, and work in southern Nevada. Corky spot of Keiffer pear, corrected with calcium sprays applied to the fruit             Until scientists understand blossom end rot better, we are stuck with the same old recommendations that I am going to repeat here and can be found elsewhere.             Don’t waste your money on calcium sprays. They don’t work. Focus your energy on mulching vegetable beds to prevent water stress in the plants. Monitor your irrigations so that plants do not become water stressed.

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Congratulations to Andrea Meckley, the Only ASHS Certified Horticulturist in Nevada!

ASHS Certified Horticulturists (CH) are practicing horticulturists who are skilled and knowledgeable in all areas of horticulture. Those with the ASHS CH certification are required to pass a rigorous four-hour exam based on the following areas of horticulture: Landscape Design and Maintenance Production of Fruits, Vegetables, Turf, and Ornamental Plants Shipping and Handling of Final Product Propagation Monitoring and Testing, Diagnosing and Managing Plant Problems Business Practices To qualify to sit for the CH exam, applicants must have more than three years of experience or a combined level of experience and education. Continuing Education Units must be reported in order to renew certification. For more information contact the American Society for Horticultural Science. How do I become a certified horticulturist?

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