Xtremehorticulture

Xtremehorticulture of the Desert

How to Get Rid of Bermudagrass Weeds in a Tall Fescue Lawn

Leave a Comment / bermudagrass, how to, Roundup, tall fescue lawn, weed control /

Q. How can I get rid of bermudagrass now, growing in a tall fescue lawn. Bermudagrass invasion of tall fescue due to irrigation and mowing height. Keep mowing height at least 2 inches for tall fescue and keep it full and lush. A. The best way to get rid of it in fescue is to cut it out if possible and then seed the bare spots after the Bermudagrass has had time to die. The best time to do this would be about April or May when Bermudagrass is starting to green up. You’ve got to kill the Bermudagrass when its alive, which starts growing in late spring, and seed the bare areas after all the grass in that area dies. That’s tricky because Bermudagrass is a warm season grass and doesn’t start growing until about mid-March or early April. It’s easier to control fescue growing in a Bermudagrass lawn while the bermudagrass is dormant (sleeping and dead looking). The fescue in the lawn is cool season so you can begin seeding when it’s cooler. But bermudagrass is warm season so it doesn’t “wake up and start growing” until late spring. If you want to try that then I would recommend spraying Roundup (its the only systemic grass killer available) in spots where the Bermudagrass is growing in the late spring and wait about a week. Don’t use Roundup combined with any other weed killer. Just plain old Roundup. The systemic Roundup translocates and kills some of the roots of bermudagrass.  First, cut the grass in the Roundup-applied area shorter and seed directly into those spots. Because Roundup is systemic and slow acting it will continue to kill the bermudagrass. The label on Roundup prevents you from seeding any sooner than this. You should start seeing the fescue pop up from seed in about 7 to 10 days as the grass in those spots continues dying. What to Do? 1. Mow the area shorter. 2. Spray Roundup over the area without any other weed killers in it. Just plain old Round-up. The grass wont die for 2 to 3 weeks.  3. After one week, seed a high value tall fescue seed in the same area. The grass you sprayed will look like it is alive but it is dying. I would mow the area shorter, somewhere between a half to an inch tall, and apply ammonium sulfate (21-0-0) in early March. The Bermudagrass likes warm weather, as well as nitrogen fertilizer, and it will start turning green a couple of weeks earlier than when it is taller. Use a high-quality tall fescue variety to seed in those spots. The grass will not be dead yet but it’s dying, and you have to trust that it’s dying. As the new fescue seed is coming up you will see sprayed areas start to die or turn brown. You can safely seed into Roundup-applied areas 7 to 10 days after the spraying has been done. The tall fescue and Bermuda does not look dead yet, but they are dying. You can’t start killing Bermudagrass until after it starts getting green in the spring. Preventing Bermudagrass Invasion In the future keep your mowing height between two and three inches. Keep the lawn thick to choke out any invading Bermuda grass. To do this apply fertilizer to fescue lawns at least 4 times per year; Valentine’s Day, Labor Day, Memorial Day, and Halloween. The fertilizer to use is a 21-7-14, between half to 3/4 of the bag rate if you are returning the clippings to the grass (not bagging). The rate on the bag may be too much fertilizer. Don’t give the edges of your lawn of bevel cut because it encourages in Bermudagrass invasion. Instead use a steel edger perpendicular to the edge of the lawn.

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How to Prune Clematis Vine

Leave a Comment / pruning flowering plants, vines /

Q. How to prune clematis vine in North Las Vegas? Always prune “pretty plants” immediately after they finish flowering. If they flower most season long, then prune them in the winter. This picture is from another reader. A. To get a “how” it is best to send some pictures. Without pictures I can tell you “when”. Clematis vine should flower late in the spring and then again in the fall if you are lucky.  There are multiple ways to prune it depending on what you’ve got. Clematis is basically a flowering woody vine that can be pruned as if it were a shrub. The flowers grow on older wood and, depending on the variety, can flower anytime from spring until fall. If the vine or shrub flowers all season long, then winter is the best time to prune. Always prune flowering vines and shrubs just after they finish flowering. You are okay pruning now because the winter has interrupted the flowering. Did you know there is a “native” clematis? It is not as spectacular when it flowers, but it is a native and so it can handle less frequent watering. It is still a clematis!

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Brown Leaf Tips on Strappy Leafed Plants

Leave a Comment / brown edges on leaves, leaf necrosis, tip burn /

Q. What causes the brown tips on some strappy-leaved plants like iris or agapanthus? Should I cut it off? Tried to find some leaf tip burn or leaf scorch on narrow leafed plants like Mondo grass or agapanthus. No luck. It is always the same. Not enough water is applied, the soil is not improved, salty soil or water, or it was planted in a hot location. In the case of Mondo grass, it should not be planted here. The humidity is just too low for it. https://www.public.asu.edu/~camartin/plants/Plant%20html%20files/liriopemuscari.html A. You didn’t tell me which plant you’re concerned about because some plants are less tolerant of certain location than others. This browning of the leaf tips is called plain old “leaf scorch”. It can be caused for lots of reasons; sun is too bright, low humidity, windy locations, poor periodic soil amendments, watering too frequently, salty soil or irrigation water, or watering not often enough.             For instance, Mondo grass (it is a form of Liriope muscari or grape muscari) is a small plant with “strappy leaves” with lots of different common names like border grass, monkey grass, grape hyacinth, and others. It gets leaf scorch in the desert in ALL locations. That’s the way it looks in the desert. When in doubt, call it by its scientific name (or Latin name) and understand where it is from.             Getting back to your plant, do what the gardeners in the hotels do to indoor plants. They cut the leaf scorch off and make the ends of the leaves resemble others. This makes the plant leaves look more “natural” to passerby’s who just glance at it or pay no attention. If most of the remaining leaves are pointed, then cut it off in a point. If you end up not liking the look, remove the entire leaf by cutting it off at its base and hiding the cut.             I know I sound like a broken record but, when pruning, always sanitize the blades with at least 70% alcohol when starting.             Consider moving the plant to a more hospitable location. If it looks like the leaves are scorching, then move it to a shadier spot. If that doesn’t work and you remove it, then lesson learned. Consider it part of your education. Learn the name of the plant and buy something different.             Remember, plants that have showy flowers need more light than those that don’t conspicuously flower. If you planted a nonflowering plant and it was planted at the lowest level of light available, then the same plant will not work in that spot. Either that or more light needs to be made available.

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Bitter Orange a Good Choice for Las Vegas But….

Leave a Comment / bitter orange temperature, citrus, cold damage, las vegas landscape /

Q. Is it possible to grow sour or bitter orange in Vegas? It’s becoming almost impossible to find at the local markets and we use it in so many recipes. I was curious if that was something that might grow here? When should I plant it? Bitter orange, sometimes called trifoliate orange, is a good choice for colder climates like Las Vegas where it oftentimes freezes. A. They aren’t very popular here. I understand why you might want to grow them. We are talking about Citrus aurentium. They are used as a landscape highway plant or landscape hedge in the Phoenix area where it’s warmer during the winter. Here they are mostly used as a low temperature rootstock for citrus when shipped to our area by wholesale nurseries. Trifoliate orange is used primarily as a freeze tolerant rootstock for our area, but sour orange is also used. Sour orange is used as a rootstock for citrus needing to be cold hardy. If the top of a citrus dies due to freezing temperatures, at least the rootstock will sprout and grow after the top freezes. I don’t have the information on their low temperature tolerance for the winter, but I think it’s around 20° F so it would be a good choice for planting in the Las Vegas area. Meyer lemon and kumquat, two more commonly grown citrus here, will handle freezing temperatures to about 24-25° F. once established. In protected backyards Meyer lemon, grapefruit, and kumquat survive most of our winters. So, my guess a fifteen-foot sour orange will be at least reach those temperatures, if not a bit lower. This tree should start flowering in about year four to six. You will still lose fruit due to early spring freezes combined with open flowers in some landscapes depending on its exposure to early spring freezes and wind. But the tree itself should survive our annual fluctuating freezing temperatures for about 25 years or more. Remember ALL citrus are from China and parts of southeast Asia. This means the desert soil needs to be amended at the time of planting, and periodically adding amendments to the soil. No citrus are xeric so they will need about the same amount of water as regular fruit trees of a similar size, about 4 to five feet of water under applied under its canopy in one year. Just for your information bitter orange does get a deadly disease occasionally but it’s usually not prevalent in non-orchard citrus areas so you should be all right. Buy the tree smaller and protect the tree from sun damage through shading itself or providing it shade while it gets established. Buy a tree that is shrublike. You won’t find it locally. It is not that popular as a tree on its own. I think you will have to order it online. Places outside of the desert southwest don’t have to worry much about sun damage to the trunk so it is limbed up higher into a tree. For this reason, you want to buy it grown into as much of a bush as possible. Limb it up later when it gets older and acclimated to our desert. The best places to order it are from Arizona nurseries such as Whitfill or Greenfield if they will ship it to you. Both are in the Phoenix area. Plant it when temperatures are cool, but spring planting is best in the case of citrus. Because of digging and availability, most nurseries sell bareroot trees in the spring. Bareroot trees need to be planted as early in the spring as possible. Potted or container trees can be bought anytime but planting them is always best in the spring. If it were totally freeze tolerant, or you were sure it will not get extremely cold this winter and you can find it available, then fall planting is always best.

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Root Rot on Pines?

Leave a Comment / broken, Pine tree, root rot, stem broke, wind damage /

 Q. I have several very large pine trees that have been in ground since 2002. Due to heavy winds, one was felled, and the trunk broke. Upon inspection, it looked like root rot! Can you advise how much water these trees need in winter and summer. I want to be sure the see does not happen to others. A. Make sure the trees have water applied to a wide area, equal to about half the spread of their canopies. Tree roots follow applied water in the desert. Pine trees are relatively deep rooted. For this reason, apply water to them deeply. However, if the soil is hard, and the water applied too rapidly, the water may begin puddling and the tree can blow over easily. Watering plants in the desert tells them where you want their roots to grow. The roots of any large tree near a wall is a “recipe for disaster”. This large pine tree eventually heaved this wall when the roots “grew looking for water”. The roots heaved the wall. The other problem is watering. If they are given small drinks of water frequently (think planting in lawns) they develop roots that are shallow and will not hold them upright during strong winds.  When planting pine trees it may be a good idea to plant other smaller shrubs around its canopy. Pine tree roots will grow where the shrubs area as well and help support it. Unless you know what you are doing, it may be a bad idea to have a pine tree planted all by itself surrounded by desert soil that is not irrigated. These trees will blow over.  Place plants around the pine tree that are throughout its canopy as it grows larger. Putting irrigated shrubs around pine trees helps the pine tree roots to grow into the surrounding soil and become more firmly anchored. It is not something mystical about the surrounding plants. It is because these plants are irrigated, and they share water with the pine trees.

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When to Stop Cutting Asparagus

Leave a Comment / harvest asparagus, how long, when /

Q. When should you stop cutting asparagus? We’ve had a good crop in the past but seem to have quit harvesting too soon in prior years so want to go as long as possible. We enjoy eating it! Asparagus spear called ‘Purple Passion’ harvested A. The textbook answer is 6 to 8 weeks of cutting and then you should let it go and rebuild its crowns beneath the soil for next year’s harvest. That information was given back when asparagus spears were thought to be marketable only if they were the diameter of your thumb. That’s changed and now we see asparagus sold much smaller in diameter than that and marketed as such. Asparagus spears will produce spears large in diameter at first but after the crowns get exhausted from production the spears will get smaller and smaller in diameter. It is up to you when to stop harvesting them. But in the older days, asparagus spears were harvested until the spears got smaller in diameter and smaller. The other answer is to continue to harvest until you see a noticeable decrease in the diameter size of the spears. When they start to get too small for harvesting (don’t just look at one spear but take an average), stop and let the roots and crowns of asparagus rebuild themselves.             Asparagus will rebuild itself better if you can provide some nutrients as the crowns are putting away storage for next year. After harvesting, apply at least an inch of rich compost or you can also use manure. In late December or early January the asparagus bed is fertilized with either manure or a rich compost. Sometimes a fertilizer is required if no manure or rich compost is available.             The crowns should be 6 to 10 inches deep depending on the soil so laying manure on top of these areas should cause no problems. (Some manure is high in salts.) Planting the crowns deep makes sure the spears don’t come up too early. Make sure you water it after planting. After planting don’t water too often because the crowns are deep. Apply water on a similar irrigation cycle as fruit trees. The roots and crowns should have water available at the same depth. Asparagus crowns are planted 8 to 10 inches deep. In retrospect, I would have used more compost when planting and made the planting area darker…more organics in the soil.

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