December 2014 – Xtremehorticulture

What Causes Brown Leaves on Yucca?

2 Comments / desert plants, what causes brown leaves, yucca / xtremehorticulture

Q. Why are the tips of my yucca leaves turning brown? Brown leaf tips on yucca. Can be from soil or irrigation problems. A. This is pretty common on yucca in our climate and soils unless they are grown in filtered sunlight and the soil has been prepared well before planting. They always tend to have brown tips. In the case of your plant, judging from your picture, it does seem excessive. When we see brown tips on the foliage of desert plants it usually means a watering problem, a soil salt problem or lack of drainage. This particular yucca is native to the Chihuahuan desert so infrequent irrigation is critical to its health. Most of the soils in the Chihuahuan desert are better than our landscape soils created by the builders of our homes. Regarding your irrigations, compare your watering with how these plants might be watered in their natural habitat. This is a guideline for how you should water. They won’t need watering that often so if you are watering more frequently than every two or three weeks in midsummer, I would suggest this is too often. If this plant is on the same irrigation circuit as other landscape plants, and these other plants are not a desert plants, then I would suggest the plant is being watered too often. The volume of water you give the plant is not as critical as the frequency it receives water. In other words, you can give it a large volume of water and not hurt the plant as long as you wait long enough before the next irrigation. Giving large volumes of water may waste water but it seldom keeps the soil too moist for the plant between irrigations. If this plant is watered too often, remove it from that irrigation circuit and water it by hand every few weeks. It will like a couple of deep winter irrigations, a spring irrigation, a couple of midsummer irrigations and a fall irrigation and that’s about it. If the applied water is close to the trunk, then the trunk could be rotting. Keep frequent irrigations away from the trunk. However, it is okay to water in a large basin beneath the plant if it is done infrequently. If there are other plants around it, it is probably getting enough water from its neighbors. But I would still give it an occasional drink to be on the safe side.

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Can I Apply Iron in the Winter?

Leave a Comment / applying iron sprays, when to apply iron chelate spray / xtremehorticulture

Q. I have a dwarf lemon tree with many yellow leaves. Can I add iron at this time of year (December)? This is not citrus but it is iron chlorosis. You can tell from the yellowing of the leaf while the veins remain green and appearing on the newest growth. It is possible to confuse it with manganese deficiency easily. A. If you apply iron this time of year (December) it is best applied as a foliar spray rather than to the soil. If the leaf yellowing is not extensive you could wait until spring. Leaf yellowing reduces a plant’s ability to capture sunlight and produce energy to maintain its growth and health. Iron chelate made for applying mixed with water. If you want to correct it now, you must apply iron to the leaves as a liquid or foliar spray. It is best to use an iron chelate mixed with water and add about 1 tablespoon of white vinegar if you use tap water to reduce the alkalinity. If you use distilled water, you will not need the vinegar. To this water add the appropriate amount of iron chelate listed on the label. You should add a wetting agent to help the spray penetrate the leaves. You can make your own wetting agent by using a liquid detergent like Dawn or Ivory Liquid at a rate of about 2 teaspoons per gallon added to the finished spray mix. It is not as refined as a commercial wetting agent but it will do the job. A very safe wetting agent for better leaf penetration You would apply this mixture of water, chelate and wetting agent to the leaves immediately after mixing it until the spray runs off the leaf surface. Let the leaves dry and repeat it a few days apart or until you see the leaf color change from yellow to a darker green. Foliar sprays like these may require several applications to get the results you desire. Citrus leaves have a very waxy surface and are difficult to penetrate with just plain water. If you use tap water then each time you prepare a new spray you should adjust the alkalinity of the water with vinegar and add a wetting agent. Foliar sprays should always be freshly made, applied immediately and not stored for any length of time. Unfortunately homemade iron liquids, unlike commercial sprays, do not store very well. It might be cheaper in the long run to buy the liquid iron spray already made and make the application. It is also possible citrus leaf yellowing could be a magnesium or manganese problem. Liquid iron sprays will not correct problems due to magnesium or manganese.

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Radishes Are the Perfect Winter Vegetable for Beginner Gardeners

Leave a Comment / how to grow radishes, how to harvest radishes / xtremehorticulture

Radishes are the perfect winter crop for the beginner gardener in the ground, raised beds or containers. They are easy to grow, will germinate at very low soil temperatures and will mature for harvesting in as little as 30 days. Don’t plant them too deeply and to speed germination cover with some clear plastic to keep the soil warm. Remove the plastic after you’ve seen them germinate. Space the seed in rows or in blocks so that the seed is about 1 to 2 inches apart from each other. In our Las Vegas climate you should be able to get 5 to 6 crops during the fall, winter and spring seasons when they are the sweetest. Find some hybrid varieties which will reduce the heat or spiciness if you don’t like that. The tops can be eaten in a salad or cooked as greens just like mustard greens. The oil that you use in cooking greens has a big impact on the flavor of cooked greens. French breakfast radish after 30 days Spacing of radish seeds. If radishes are too close together they will not produce large bottoms.

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Brown Ugly Space Alien in the Garden

Leave a Comment / brown shell in the garden, hummingbird moth, sphinx moth, what is this brown alien thing in the garden / xtremehorticulture

Recently I found this brown space alien into one of our raised beds. This is the pupa, or resting phase, of the tomato hornworm. This is the stage of development between the worm or larva and the adult hummingbird or sphinx moth. This insect is a voracious feeder of all garden plants but particularly tomatoes, peppers, eggplant and even grapes! This insect will overwinter in this stage and emerge again in the spring as the adult hummingbird moth. It will find a mate by flying at dusk and lay eggs on plants that it likes to eat. The eggs will hatch into a miniature hornworm and voraciously grow into the much larger version. Hummingbird or Sphinx moth Right now you can dispose of them. But later in the spring after planting you will want to protect your plants with either Bt or Spinosad. Bt can be found under the names of Dipel or Thuricide as well. One of the names for Spinosad. Check the ingredients

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Delay Pruning Grapes Until Very Cold is Past

Leave a Comment / How to prune grapes, when should I prune grapes / xtremehorticulture

Q. I usually prune my grapes when I do the roses but would like to get a jump on it this year. Will I do them any harm if I prune them now (December)? A. You can do it but I worry a little bit about possible freezing damage if these are winter tender grapes and desiccation. Some grapes are less cold hardy than others. For instance, Thompson seedless has some wine grape heritage (vinifera) and tends to be less cold hardy than some other table types. I have noticed in our desert climate that we can also get winter desiccation (drying out) in windy locations. Those grapes which are pruned to spurs usually leave only one or two buds which means the spur may only be one half inch long after pruning. If we lose this half inch of growth from winter cold or desiccation, then we have lost our crop for the season. I usually delay it until almost the first week in March when buds are starting to swell. By delaying it I can prune out the dead wood that occurs during the cold winter months and focus on the stuff that is still alive. I would wait.

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Swarming Bugs; Ants or Termites?

1 Comment / flying ants, flying termites, how to tell the difference between ants and termites / xtremehorticulture

Q. We were out in our yard last weekend putting up decorations when we noticed small bugs flying up out of our yard. They were thick groups of them coming out of small holes that looked like grains of rice clumped together in bunches. There had to be thousands of them. The “exodus” lasted for about an hour and then it was done with no sign they had been there. Can you tell what they are? Are they harmful? Do we need to do something to get rid of them? Flying ants or termites. The length of the wings suggests termites but a visual check of the bodies and antennae need to be done. A. These look like winged ants or possibly winged termites. It was difficult to tell from your picture. They both swarm in identical fashions. The ants are just a nuisance. If these are termites then you may have a problem. You need to catch some of these insects and look at their body shape, antennae and length of their wings. Ants have a constricted waist or segmented body parts. Termites do not have these segmented body parts and body parts are not as easy to distinguish. I have provided a link on my blog for you to follow or you can type the following into your search engine that will help you identify the difference between the two different insects. How to tell the difference between ants and termites If you believe these are termites contact a reliable pest control company and schedule a follow-up. Follow the link below or on my blog to read information about flying ants from Colorado State University. More about flying ants

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When Should I Winter Prune Flowering Plants?

Leave a Comment / how to prune flowering plants, when should I prune / xtremehorticulture

Q. I have some bushes and shrubs in my backyard that still seem to be blooming. How do I know when they are ready to be trimmed back? A. Sometimes we have to prune them back to make way for new growth in the spring. For small plants that get a lot of woody growth at the base, let them go through the winter and trim them back after all of the very cold weather has passed this winter. That is usually by mid-February. Lantana after winter pruning. This was actually left too long. Prune closer to the ground. After pruning, this is what you will look at until February. Pruning of ornamentals is all about appearance. If it looks bad to you, go ahead and prune it back. You will not hurt the plant. My major concern about pruning too early is the possibility of freezing damage and creating more work for yourself. If you prune now and we get more freezing weather then you will have to prune a second time. Waiting until the end of the coldest part of the winter avoids pruning a second time. But if you like to go out in the yard and tinker, prune when you need to. It won’t bother the plant.

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Harvest Oranges Before a Hard Freeze

Leave a Comment / citrus, when should I harvest oranges / xtremehorticulture

Q. After 6 years, I am finally getting oranges. They are turning orange and I have been told not to pick them until mid January. Is this right or can I pick them now (mid-December)? A. Different varieties ripen at different times. I would sample one now and if it tastes good to you then harvest the others at the same maturity. If it is not yet to your liking then wait a bit but if temperatures drop to the mid-20’s then the fruit might freeze. In the Las Vegas area we get our coldest weather NORMALLY from mid-December to the end of January. Play it by ear a bit right now but normally they would be ready right about now. You do not want to wait too long because fruit remaining on the tree can interfere with new flower production. I copied and pasted this citrus calendar from the University of Arizona pdf document you can download from HERE. These are the approximate harvest dates (this is for Maricopa County, aka Phoenix area). We are a bit colder so harvest times can be a bit later. However for areas like Laughlin and Bullhead City they would be on the mark. Note: I am recommending citrus in the Las Vegas area in only warm microclimates or protected from winter cold and winds. The chart below I copied and pasted from the University of California Riverside pdf document you can download HERE. This tells you the critical temperatures where you might lose different parts of the tree (flower buds, blossoms, green fruit, ripe fruit).

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Will Buffalograss Grow in the Mojave Desert?

2 Comments / buffalograss, how do I grow Buffalo grass, Will Buffalo grass grow in the Mojave desert / xtremehorticulture

Q. Will Buffalograss grow in the desert? A. Buffalograss grows perfectly well in the Mojave desert. The major problem is finding a source for it. I would not start it from seed if you want a good quality lawn. The best method would be to use sod but without a source of sod locally, you could have plugs shipped in from a reputable supplier. Buffalograss can make a good quality lawn if you started from sod or plugs but not from seed.. Buffalograss is native to our dry grasslands and prairies of the United States. Like Bermudagrass and zoysia grass, it is a warm season grass which means it will become dormant or go to sleep during the winter months. It is best planted when soil temperatures have begun to warm in the spring or very early summer. Preparation of the soil is very important for good establishment. Plugs are normally at least 2 inches in diameter and spaced 12 to 24 inches apart in the lawn area. Because Buffalo grass is a sod forming grass it fills the bare soil between plugs with stolons or surface runners. With good management the lawn area should be completely filled before it gets cold in the fall. This is a bit controversial but research in Arizona has demonstrated Buffalo grass to use about the same amount of water as Bermuda grass but it does not require the fertilizer or the same level of management. A reputable supplier out of Nebraska is Todd Valley Farms. Give them a call and talk to them if you are thinking about Buffalo grass.

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