Xtremehorticulture

Xtremehorticulture of the Desert

Crabgrass Control Now?

Leave a Comment / Controlling crabgrass, Flame weeder, herbicides, pre-emergent weed killers /

Q. What steps can be taken this time of year for crabgrass invasion? Crabgrass, not the readers. A. It is now August. If you correctly identified your weed as crabgrass, there is nothing that you can do now except remove them by hand or do some hand weeding. Crabgrass will die when it freezes hard this winter. If it is in a location where it does not freeze, or lightly freezes, then it will survive and grow more the following year. All you can do this time of the year is soak them with water and pull or rogue them out. You can also burn them back if it is allowed. Propane weed flamers or torches work well if you use them in an area that will not continue to burn. The seed, however, will still be there on top of the soil and unaffected. The seed germinates in the spring around the middle of February in our climate or perhaps earlier if it is warm. I purchased one for weed control on my small farm in the Philippines. The more powerful ones like mine will even weeds that are wet or after a rain. Very important in the Philippines. Flame weeder I purchased Pre-emergent herbicides or weed killers can be applied about the middle of January to prevent crabgrass from germinating and getting a foothold. It should be reapplied about six weeks later or when the label tells you to. But this time of the year, all you can do is pull, burn or dig them out.If you buy a pre-emergent weedkiller for crabgrass make sure it lists crabgrass on the label, destroy any crabgrass that survive past the end of January and apply this herbicide by mid-January in our climate.

Crabgrass Control Now? Read More »

Clover-Looking Weed with Yellow Flowers is Very Difficult to Control

Leave a Comment / herbicides, iris, Las Vegas, lawn, Mohave Desert, Mojave Desert, nevada, oxalis, shrubs, weed control /

Q. I have oxalis clover look-alike as a weed. How can I control it? I am ready to use chemicals at this point having tried to rid it by digging and pulling with no success. Having it in my grass is bad enough but now that it is in my iris beds I want to kill the dang stuff! Oxalis looks like clover but has yellow flowers that resemble a daisy with only five petals. A. Oxalis is very difficult to kill. It may require repeat applications but one of the keys is to try to kill it when it is “happy” and is ready to grow and multiply. This is usually spring and fall. Go to your favorite nursery or garden center (you may have to look at several such as Lowes, Home Depot, Star and Plant World). Go to their weed killer section. Look at the active ingredients. Look for the following in the active ingredients list. The important chemicals to find on the label are either Dimethylamine salt of dicamba: 3,6-dichloro-o-anisic acid (it may be just called dicamba or Banvel) somewhere on the label. The alternative would be an ingredient called triclopyr, (chemically called 3,5,6-Trichloro-2-pyridinyloxyacetic acid) These chemicals are usually combined with other weed killers for better synergism (efficacy or improved performance). In cases of herbicide synergism 1+1 = 3 times more effective. So you may see 2.4-D listed as the first chemical (Dimethylamine salt of 2,4-dichlorophenoxyacetic acid) or you may see 2,4-DP (mecoprop or Dimethylamine salt of (+)-(R)-2-(2 methyl-4-chlorophenoxy) propionic acid) listed as well on the label but the names in RED are the most important for oxalis control. I am sorry for the detailed technical response but this is really technical stuff to get you the right chemical. There are so many different manufacturers and labels with the same stuff in it, it is impossible to list them all so giving you the ingredients to look for is much easier. Next is the method of application. These chemicals will not damage a lawn if you apply at the right concentration but they WILL damage other plants. So you must spray them directly to the weeds and not overspray onto other plants!  Make sure you wear waterproof gloves when mixing and applying and wash thoroughly after an application. They are not THAT toxic but it is always a good precaution. Never spray on a windy day. Spray when weather is warm but not hot because the plants are better able to “absorb” the spray.  Mix about 1 tsp of ivory liquid detergent per gallon of spray to the finished mix and thoroughly stir it. Do not add it before you add water or it will just give you a lot of weed killer bubbles. This detergent helps the week killer enter the leaves.

Clover-Looking Weed with Yellow Flowers is Very Difficult to Control Read More »

Controlling Bermudagrass Growing in…..

Leave a Comment / bermudagrass, control, devil grass, devilgrass, herbicides /

Common bermudagrass stolons creeping from the lawn over a sidewalk. Hybrid bermudagrass is much more restrained in its growth. This is a queston frequently asked, “How do I control bermudagrass in……” so let’s talk about it. The big problem is common bermudagrass. It is spread by seed, underground stems called rhizomes that can grow under the surface of the soil for many feet and re-emerge in a new location. Sort of like “Whack-A-Mole”. You pull it or spray it here only for it to popup over there. Below ground the bermudagrass cannot get the energy it needs from sunlight. It must rely on food supplies sent by the mother plant growing in sunligh OR live off of stored food in its stems. It can also spread by planting, or accidentally planting, any of its stems above or below ground. For instance you can take the above ground growth, cut it up into small pieces, throw it on the ground, water it and it will start a new plant any place these cut up pieces fall. When we WANT it to spread like this, we call are planting by stolons or “stolonizing” the area. The hybrid bermudagrasses, the kind that are nice to grow like on golf courses, is planted exactly this way. The underground stems that spread the mother plant to a new location all by growing underground are called rhizomes. The only difference between the above ground stems (stolons) and the below ground stems (rhizomes) is there location AND their propensity to either grow above or below ground. What you can do to stolons, you can do with rhizomes essentially. So if you cut up a bunch of rhizomes the same way as stolons and spread them on the soil surface, guess what will happen. You got it. You have a new lawn whether you wanted it or not. Hybrid bermudagrass stolon (left) stem and leaves (right) and rhizome (bottom) Question for YOU. What will happen if you rototill a bermudagrass weed area in the hopes of getting rid of it? Answer: You spread it. So how do you get rid of bermudagrass weeds? You exhaust it. You kill it, let it grow a bit, kill it again, let it grow, kill it again, let it grow, kill it again…… In this way you begin to exhaust its stored food supply AND by constantly killing or cutting off its access to sunlight you deny it the ability to put more stored food into its food supply. In the end you exhaust it, weaken it and it dies. You can deny it sunlight by constantly killing top growth back as soon as it gets exposed to that life-giving light a week or so. You can kill the top growth by mechanically whacking it off to soil level or below or killing it to the ground with a poison such as Roundup or even vinegar. Anything that will cause it to die to the ground and not hurt the surrounding environment. The advantage of Roundup is that it is systemic and will travel into the ground a distance and kill somewhere below ground level. To grow back requires more energy and so it will be more effective than just whacking it off or killing the tops. The disadvantage is that it is a weed killer and it may have some adverse side effects. Other chemicals to look at include Poast and Fusilade which are also systemic weed killers and are potentially less damaging to surrounding plants. Nothing wrong with a hoe, shovel and other tools that will help take it to the ground. Regardless, the secret to success will be to stay on top of it and never let it grow back more than a few inches before you knock it down again.

Controlling Bermudagrass Growing in….. Read More »

Preventing Weeds From Growing on Top of My Weed Barrier

Leave a Comment / geotextile weed barriers, herbicides, preemergent herbicides, weed control, weed control without chemicals /

Q. Weeds that infested an area of my yard – there is a screen like barrier just under the top soil. My question is what can I do to prevent this in the future without killing the shrubs in this area and what is the best method to eliminate the weeds that do emerge. I pulled and dug these and don’t want to have to do that again in the future. Weed barrier or geotextile under nursery containers to prevent weeds from growing A. I am assuming the screen like barrier may be a geotextile used to prevent weeds that might germinate and grow up underneath and through it. These are frequently laid on the soil surface with a 2 to 4 inch surface mulch applied on top of it. The surface mulch helps to shade the barrier and prevent the germination of weed seeds beneath the barrier. We do not use sheet plastic for this purpose. That is a huge no-no which is another topic in itself. Weeds such as bermudagrass and nutgrass can grow through the barrier and the mulch but it can be very effective in preventing other weeds. If bermudagrass and nutgrass weeds are close to a source of water such as a drip emitter or a leaky hose they will have no difficulty growing through the barrier and through the mulch. Weed barrier down. Lets air and water through to the soil. The other problem with textile barriers covered in mulch is that windblown dirt is trapped by the rock mulch and falls on top of the textile barrier. Over time, this windblown dirt accumulates and forms a soil layer on top of the textile barrier in amongst the rocks. Weed seeds then blow over the rock mulch or might be carried by birds where they fall between the rocks and onto the soil on top of the barrier. If there is rain or a source of water, weeds will flourish and the textile barrier appears to fail. The barrier has not really failed. The accumulation of windblown dirt on top of the barrier is a major culprit. Weed seeds below the barrier are still prevented from penetrating the barrier and making it to sunlight. Geotextile barrier There are three things which you can do to help prevent weeds from getting established. The first is to make sure your sources of water are limited to only where the plants are growing. If you have water that is spraying onto the rock mulch or puddling into open areas from other sources than you are going to have problems. It is imperative to make sure water is contained in the area where plants are growing. Secondly, it is best that mulches are deep. A 4 inch layer of mulch is much more effective at controlling weeds than a 2 inch layer. Coarse mulches are more ineffective at controlling weeds than fine mulches. By a coarse mulch I mean rocks that are at least 1 inch in diameter.           Thirdly is the point you are probably not going to like and that is staying on top of weed growth. We have an old saying as gardeners that basically says one year of weeds leads to seven years of weeding. This just means that if you fail to control weeds in your garden area and let them go to seed then the seeds released by these weeds will lead to seven years of weeding. It is so very important to stay on top of your weeds and get them removed before they form flowers. There are several types of garden hoes that are very effective. For bare soil or very fine mulch I like the diamond hoe. For larger mulch pointed hoes or even a shovel works well. If the weeds are relatively large, spraying the area with water from a hose and hand pulling weeds about 15 minutes later is very effective as well. Black plastic when laid under rock starts to poke through in a couple of years. Very ugly. Black plastic is a temporary mulch and rock is a permanent mulch.           To aid the gardener chemical companies have developed weed killers that can kill seeds as they are germinating or kill the plants after they have grown from seeds. Many of them are very effective however you are applying and unnatural chemical which is potentially, and in varying degrees, dangerous to other plants, animals and our environment.           Check with your local ordinances but there are devices which use fire to control weeds. These frequently operate off of LP gas with some sort of torch. These are also potentially very dangerous and should be used with extreme caution.           In a nutshell, there is no magic bullet except to make sure water goes where you needed to go, increase the depth of your mulch layer and stay on top of your weeds and do not let them go to seed.

Preventing Weeds From Growing on Top of My Weed Barrier Read More »