Xtremehorticulture

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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Leafcutter Bees Will Probably Use Houses for Blue Mason Bees

Q. Someone gave us a Mason bee house to use. I saw in a July 2011 post on your blog that there really aren’t mason bees in the Las Vegas area but there are leaf cutter bees. Do you think the leafcutters would use the Mason bee house? I know leaf cutters stuff the hole with leaves so the fact that the Mason bee holes are larger might not be an issue. A. I think the holes will be fine. The leafcutter bees will take holes up to 3/8 inch easily and I think mason bee holes are about 5/16 inch which should be fine for both bees.             Most people don’t know the difference but be delighted that local bees are using it. Have fun with it! House for leafcutter bees

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Artificial Grass Not Damaging Lemon Tree

Q. My lemon tree is about five years old and it has a lot of flowers and tiny lemons.  The tree looks healthy but I have noticed the leaves are turning yellow.  I water it every day about ten minutes, six days a week.  We have artificial grass about a foot away around the trunk.  Am I overwatering it or is it the artificial turf the culprit? A. I don’t think the artificial grass has anything to do with it. I suspect that maybe the soil is being kept too moist. The artificial turfgrass may be acting like mulch and keeping the soil wet longer than if it were not covered in anything.             Water deep and infrequently. It should do okay watered twice a week now with about 20 gallons or so each time.             Try getting some iron chelate spray and spray the foliage in the cool morning hours. Add some spreader to the spray to get it to go into the leaves or use some liquid detergent but be careful of store bought liquid detergents. It is possible they can cause some leaf damage if you aren’t careful with them.             You have to spray liquid iron about four times; once every couple of days for four sprays total. Spray until the iron solution drips from the leaves. Make a new batch each time you spray and use the spray fresh each time because of our alkaline water.

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Cold Damage is Different for Different Oleanders

Q. For the past couple of years my oleanders have suffered severe frost damage and slow to recover in the spring. They are all mature plants.  While I was trimming the dead leaves recently, I noticed that the oleanders with red flowers had less damage and were recovering more quickly than the others that have pink flowers. Is this unique to my yard, or have you heard of this from other gardeners? I’m considering removing the ones with pink flowers because they look ratty for so long and not earning their keep. A. The different colors of oleander represent different varieties. And yes, they have different tolerances to cold.             If you are not having luck with one variety, take it out and replace it. The most cold tolerant seem to be the red ones and white ones. I am not saying not to plant other colors or varieties but if you want a sure thing with no cold damage stay with white or red types. Cold damage to oleander.

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Can I Use Chipped Pine for Mulch Around Fruit Trees?

Q. Our neighbor’s pine trees are going to be cut down soon. I would like to use the wood chips from the tree as mulch for our recently planted fruit trees. I remember you recommend 4 inches deep. What are your thoughts on fresh mulch as this? A. Nothing wrong with fresh pine chippings. We provide an assortment of wood chips, fresh, at the orchard for the public. You will have no problems with it. As it is decomposing make sure you give the soil some extra nitrogen amongst the bark and soil. Collectively we call this “Green Waste”. It would normally be taken to landfills where it is a waste of a natural resource. Community mulch pile at the Orchard in North Las Vegas. The mulch is supplied by local tree services like First Choice Tree Service. We exclude palm and mesquite from the mix due to hazards from thorns and poor breakdown of wood like palm with very thick fibrous wood.             Keep any wood mulch away from the trunks of new plants about a foot for the first few years until the bark on the trunk gets woody. If they grind out the stump of the tree with a stump grinder, those are some of the best wood chips. Good luck!

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Smokey Grey Color in Your Lawn Means Water

If you see that smokey, green or grey color in your lawn it is a good sign that the grass is not getting water in those spots. Check for blocked or broken sprinklers in that location. Grey color in lawns is usually from wilting and it is the first stage before it turns brown. Catch it early and run an irrigation cycle to relieve the drought stress then discover the cause. Grey green or smokey color in a lawn is due to lack of water reaching the leaf blades. The leaf blades fold or roll up, depending on the type of grass, and reflect light differently. Regardless, it is time to hit the irrigation button. This is a closeup of that spot and if you could look at individual grass blades you would see that they are no longer open. They either rolled or folded (this is fescue so they rolled) depending on the type of grass. Get water on it immediately and fix the problem. In the top picture this has been a problem for awhile because the spot has already started to turn brown and grass started to die due to drought. Either the spray head is blocked or plugged most likely.

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