Xtremehorticulture

Texas Olive Froze at 25F or More

Q. I have a Texas olive tree that may or may not have survived this past winter. We have had the tree for several years now and it has always bloomed and grown. I don’t have any new leaves or blooms except the suckers on the bottom.  All our other trees like our sumac, Palo verde, and fruit trees are doing fine.  But not this one. Is there anything I can do at this point beyond just watching it? Texas Olive, Cordia boisieiri, hardy during the winter to about 25F, about the same winter temperature as Myers Lemon. A. That particular tree, Cordia boisieri, is native to the desert southwest Chihuahuan desert and survives to a winter temperature of about 25F; around the same winter temperature as Myers lemon. Because it’s from our desert southwest it is considered xeric in its water use. Lots of good that does you if it is winter killed or severely damaged.  A better choice might be Littleleaf cordia, a smaller tree and found growing on East Flamingo in Las Vegas. A better choice might have been another xeric tree from that area such as little leaf cordia, Cordia parvifolia, which seems to survive to a slightly lower winter temperature. I suggest in the future, permanent trees in your landscape should have a minimum winter temperature of 20F. Suckering from the base is a good indicator it died to the ground, or the trunk was severely damaged. You do not need to replace the tree unless it looks horrible. It is grown on its own roots. Let one or more of the suckers replace what died. Suckers grow very quickly if the roots were not damaged. If a tree does not normally produce suckers at its base, the production of suckers can sometimes indicate the trunk is damaged either from borers or sunburn or both! If you decide you want to keep it, water deeply and infrequently and fertilize it in the spring. Two handfuls of tree and shrub fertilizer about two feet from the tree each year will be enough. Wet the soil, create a slit in the soil with a shovel about 6 to 8 inches deep, drop the fertilizer into the slit, step on it to shut it and water it in. Xeric trees grow rapidly with water applied to them like mesic trees. You will have to search to find this tree at local nurseries.

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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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Peas Not Germinating Evenly

Q. I have had problems with germination of peas. Placed directly in prepared soil germination has been inconsistent and I had to reseed several times. Remembering a technique I learned years ago I diluted a quart of tap water with 1/8 teaspoon of laundry ammonia and watered them with that. In 2 days ten germinated and in 3 days almost all came up. Have you ever heard of this technique? Harrisons peas and trellis. Nice veggies!  A short disclaimer. This is submitted by someone in Las Vegas who is a very good gardener and this does not represent his question very well! Sorry Harrison! But anyone who can grow bananas here for the past few years is a good gardener. I will post his pictures soon and ask him to submit how he did it. A. No, I have not and that is pretty amazing! In every instance I can remember I do not remember peas being hard to germinate.             A technique I use with large seed like corn, peas or beans is to soak the seed in water prior to germination. I will put a small amount of fertilizer in the water as well. I would soak them for 6 to 8 hours before planting.             This is called “pregerminating” the seed. Using this technique usually cuts off the germination time a day or two in warms soils. I will also do the same thing with garlic cloves before planting. I usually get much faster and more even emergence from the soil.             Sometimes I think garden soil is too “fluffy” and sometimes seed has a hard time staying wet enough in dry soils for good germination.  Seed germinates better in a “firm” seedbed. Not hard, but firm. After garden soil preparation and if you walk on it, your feet should not sink more than an inch into the soil.

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Stems of Beans Devoured at the Base

 Beans planted in cool soils can get collar rot or get devoured by cutworms Q. I found a couple of beans in my garden that have been devoured at the base. Could it be some sort of soil born larva or possibly a virus?  Any ideas would be helpful. I did find one small white worm about a half of a centimeter long near the root about an inch away.    A. It could be a couple of things. First, with cool weather and cool soils it might be collar rot disease that rots the stem at soil level. This will happen if you plant beans too early in cold soils. Some varieties of beans are more susceptible to this than others. Most likely cutworm damage             The first indicator is that some plants appear stunted and grow poorly.  I usually end up removing these plants and hope the weather warms up.              The other problem can be cutworms.  You should be spraying or dusting the soil surface around these plants with either Dipel or Thuricide, an organic pesticide.  This is the time of year you should be doing that anyway for a variety of pests in the vegetable garden.

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