Garden Answers

Weeds

Preventative early Spring weed killer?
How to get rid of bermuda grass?
How do I get rid of bindweed?
I heard about a bug that eats bindweed. Can that be right?
How should I get rid of an elm tree growing in a shrub?
How do I get rid winter grass coming up all over my garden?
Is there anything I can do to prevent weeds?
How do I kill foxtails and other annual grasses?
How do I kill grass growing through shrubs?
How to kill Elm seeds growing throughout a lawn?
Is there a safe way to kill Cheat Grass but not the other grasses around it?

Question: I've had a terrible problem with weeds the past few years, and my neighbor said there's a weed killer I should be using in early Spring. What is it and how do I apply it?

Answer: Your neighbor's probably talking about a pre-emergent herbicide. Pre-emergents work by killing seed as it germinates. They're wonderful at controlling annual weeds. (Annual weeds live for a season, die, and leave seeds that perpetuate them.)

Before you rush out and buy a pre-emergent, however, you need to determine exactly what kind of weeds you actually have. If you're not sure, grab some of the dried-out weeds left in your yard, and we'll be happy to try to identify them for you. Identification is crucial, because while pre-emergents will work wonders on your annual weeds, you'll be disappointed if you have perennial weeds: pre-emergents won't do diddly-squat to them!

Furthermore, there are actually two different types of pre-emergent which work on vastly different types of weeds. Portrait works on broadleaf weeds such as spurge, chickweed, and other broadleaf weeds. Hi-Yield Crabgrass Control works on annual grassy weeds like crabgrass and foxtails. Unfortunately, there isn't yet a pre-emergent which will work for both broadleaf and grassy weeds, so knowing what you need is very important.

Pre-emergents, as the name implies, must be applied BEFORE the seeds germinate and must be watered in well. If you're already seeing seedlings it's too late. Another consideration is that different annual weeds germinate at different times of the season. For some weeds, you could actually apply your pre-emergent now, while the application to control spurge should be applied around April first. Consequently, you may need to apply pre-emergents at different times and may need repeat applications based upon the weeds you're trying to kill. I guess the bottom line is that it's difficult to make a blanket recommendation for applying pre-emergents. The best thing you can do is to be sure you know what kind of weeds you have before you begin.

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Question: I have this weedy grass taking over my front lawn. It creeps along the ground and the runners are tough and wiry. How do I get rid of it?

Answer: It sounds like you have Bermuda Grass invading you lawn. This is one of the toughest weeds to get rid of, but it can be done. The only reliable way to get rid of it is to kill the entire lawn off where the Bermuda Grass has invaded and then replant the lawn. That’s the difficult choice you have to make—kill off the lawn where the Bermuda Grass is or resign yourself to having a Bermuda Grass lawn in time. There’s really no middle ground. This grass is a lot more aggressive than our regular lawn grasses and will crowd out your lawn grasses except in shady areas.

If you decide to kill it off, here’s how to do it. We’ll spray the lawn with a product called Hi-Yield Kill-Zall. Read the directions thoroughly; sometimes it will give you a range of concentrations to mix up. Always go for the higher strength dilution. And don’t exceed the label’s recommendation. That will often lead to burning off of the top growth, but the roots and underground stems are unaffected and will quickly resprout. You’ll also have to be a little patient to begin spraying. Kill-Zall is only absorbed into the plant through green foliage. Bermuda grass usually doesn’t break dormancy until May, so wait until the plant has started to grow and has put on a good amount of foliage before starting your sprays. In fact, the herbicide works better when the target plant is actively growing so do a good job watering; treat the lawn like you always would. You want the nicest, most lush Bermuda Grass in town and then zap it!

You should figure on three or four sprays spaced at two week intervals. The first two sprays will cover the general area, the third and fourth will be spot sprays to kill off any stubborn patches that remain. Cover the foliage of the plant thoroughly, but don’t soak the ground with the spray; remember that the herbicide is only absorbed through the foliage of the plant, not through roots. I think it’s a good idea to continue to water the lawn during this time as well. Don’t water for a day or two after you spray the Kill-Zall so you don’t wash it off of the foliage, but other than that, water the lawn as if nothing was happening. This has two advantages. First, it encourages any live Bermuda Grass to sprout and show itself. You want that because you can spray it and kill it. If you’re going through the trouble of getting rid of the Bermuda Grass, you want to get rid of it all! The second advantage is that the dead grass will start to break down if you’re watering regularly, and when it’s all dead and you’re ready to replant the lawn a couple of months down the road, you can just rototill in the dead grass. Believe me, that’s a lot less work than digging out the old dead lawn.

So there you have it. All it takes is a little courage, a little knowledge, and a lot of persistence! I know it works because I got rid of some Bermuda Grass in my own yard seventeen years ago and it hasn’t shown itself since. Hope this helps.

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Question: How can I get rid of bindweed?

Answer: We actually have a "recipe" that we hand out to folks here who come in asking about bindweed. You need a combination of two weed killers to get rid of this pesky weed: Killz-All and Weed-Out. They are both Fertilome products and should be available at most independent nurseries. Mix them according to each of their label directions in the same gallon of water. Be sure to keep the spray off of any desirable plants you may have. (DO NOT use this in your lawn unless you are trying to kill off the grass too. If you have bindweed in your lawn, just use the Weed-Out by itself. It will take a couple more sprayings than the combination.) You can spray around desirable plants as long as you keep the spray off of their foliage and you don't soak the ground around those plants. Persistence pays when trying to get rid of bindweed; you may have to spray again in two or three weeks.

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Question: I heard about a bug that eats bindweed. Can that be right? What is it and do you have such a thing?

Answer: Bindweed certainly has become a problem that most of us have to deal with at one time or another. It's a tenacious weed that can regenerate from small pieces of the root, and has a root system that spreads far and wide. Due to the widespread root system, trying to remove bindweed simply by pulling it up really isn't very efficient.

There actually is such a thing as insect control, but it's fairly new here in the valley. It's called a bindweed mite, and is a microscopic eriophyid mite that feeds ONLY on field bindweed. As the mite feeds on the bindweed, it distorts and slows down its growth. By stunting it, the flowering and seed production are greatly reduced which, in turn, helps cut down on future weeds. While this mite does eat the bindweed, it's obviously not a fast-acting solution to the problem. Over time, you will notice the difference, as they can have a significant effect; it's just not something that will magically disappear from your yard overnight.

That said, the mites are being distributed, AT NO COST, at the Orchard Mesa site of the Western Colorado Research Center, located at 3168 B ½ Road in Grand Junction. Hope this helps.

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Question: I have a Butterfly Bush, which all of a sudden has an Elm Tree starting to grow in the center of it. What is the best way to get rid of the Elm Tree?

Answer: The best way to get rid of the elm if it isn't too big, is to try to pull or dig it up, being careful not to disturb the Butterfly Bush. If it's too big for that , try to cut it off BELOW ground level. Elms often won't sprout if you can cut them off low enough. Those would be the preferred methods of getting rid of the unwanted elms. If, however, you get sprouting, you may need to use Fertilome Brush and Stump Killer which you would apply to the fresh cut ends of the stumps. This is very powerful stuff that I would only use as a last resort because the herbicide is very potent and could pose a real risk to your Butterfly Bush.

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Question: I've got winter grass coming up all over my garden. What can I do to get rid of it?

Answer: There are a number of weeds that germinate in the fall including grasses and broadleaf weeds. These are called winter annuals because of their late life cycle. They germinate in October and November, over-winter as plants or seedlings and then when the first warm weather hits (usually in February or March), they start growing, causing early problems in folks' gardens and lawns. They'll come up, flower, set seed and are usually dead by June, having left seeds to propagate for the following year. A few common winter annuals here in the Grand Valley include Cheat Grass (also called Downy Brome) and Henbit.

Pre-emergents are an effective way to control these weeds, but it's all in the timing. Pre-emergents work by killing the germinating seeds. Because of that, the best time to use them is BEFORE you see any weeds! Not easy to estimate, but around here, the best time seems to be at the end of September or the beginning of October.

You could try spraying them now with a post-emergent herbicide (a broadleaf weed killer), but they're simply not very effective. The reason for this is that as the plants are going into their dormant stages, they slow their growth. Sprays are most effective when it's warmer and the weeds are actively growing.

I've found what works well is to just do a light, shallow cultivation of the area, just taking the plant off at ground level. Hope this helps.

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Question: Weeds invaded my yard last year. Is there anything I can do prevent them from coming back?

Answer: It does feel like we're under siege by weeds sometimes. Fortunately, I do have a weapon that will reduce the combat to a one-sided skirmish in your favor—the preemergent herbicide.

Pre-emergent herbicides kill the seed of an annual as it germinates, so applying the herbicide before the seed germinates is the key to success. Germination occurs several days to one week before the seedling breaks ground. Therefore, sooner rather than later is the rule. But you also have to know your enemy—or weed.

Weeds are either annuals (they live for one year) or perennials (they live for more than one year). Pre-emergents won't be effective against perennial weeds. It also helps to know the specific weed you're trying to control. If you need help identifying your weed, bring in a sample to Bookcliff Gardens. We'll be glad to help you.

The date of application varies with the annual weed you're trying to eliminate. Chickweed, foxtails, and crabgrass raise their ugly heads in April, so you'll want to apply in mid- to late March. Spurge (my personal nemesis) doesn't pop up until May, so I'll be cranking the ol' broadcast spreader in mid-April. Also, pre-emergents come in granular forms that need to be watered in. If you're on ditch water, you'll want to make sure irrigation water is available, or use your domestic water. Repeated applications may be necessary.

For those of you wanting less toxic methods of weed control, we have a new product called Concern Weed Prevention Plus made from 100% corn meal gluten that will help eliminate annual weeds. Not only is it safe for people pets, and wildlife, it comes in a convenient applicator package. Just open, shake, and re-close for the next use.

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How do I kill foxtails?

Answer: The most effective way to kill Foxtails is to use a preemergent type herbicide. Foxtails are annuals that die every winter but leave a lot of seed to come back the next year. A preemergent works by killing the seed as it germinates. The trick to this is that you have to apply the preemergent before the weed germinates. Once it's germinated, the herbicide won't work. Around here, we'll apply it during the month of March sometime, depending on the weather. If you don't see any of them up now, you could still apply it. We sell a great product called Hi-Yield Crabgrass and Weed Preventer. It's a granular product that you apply with a fertilizer spreader and then water in well right afterwards.

If they've already germinated, it's tougher to do a good job on them. You have three options. First, pull them. I know exactly what you're thinking, but it's really not that bad! They're shallowly rooted and pull pretty easily. If they're not too thick, this is probably the best option. Just grab a glass of iced tea in the evening and spend a pleasant half hour (or two or three) out in the yard!

The second option is to spray with Hi-Yield Killz-All. This does a good job on them but it's non selective--it'll kill your lawn grass too and you'll need to reseed those areas. The last choice is to use a product called Fertilome Crabgrass, Nutgrass and Dallis Grass Killer. It has some selectivity where it will kill the Foxtail but not your Bluegrass. It usually takes two or three sprays to do it and it can yellow your lawn, but it will recover. Whichever way you choose to go, be sure to get rid of the Foxtails before they have a chance to set seed and perpetuate the problem.

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We have an area of low junipers that has grass growing up in the middle. Is there a nifty chemical that will kill grass but not the evergreens?

Answer: We sell a product called Fertilome Over The Top that would do the trick for you. It kills grasses without harming broad-leaved plants. Spray it well on the grass and do it a second time ten to fourteen days later. Be patient with this product. It will take a week or more for the grass to start to yellow, but it really does the job.

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I have Elm seeds growing all through my lawn, what can I use to get rid of them? The lawn is covered with them!

Answer: There are a couple of ways to go about getting rid of those Elms. First, you can do nothing except continue to care for your lawn. Regular mowing (at least once a week) will usually result in the seedlings dying off. They usually won't persist under those conditions. If you want to get rid of them faster, the second option is to spray your lawn with a broadleaf weed killer. I don't know what you have available in your area, but here we sell a couple of Fertilome products that work well. The first is Weed-Out. It contains a combination of three herbicides called Trimec. The second one is called Weed Free Zone. It contains Trimec plus a fourth herbicide and works very well. Neither of these products will hurt your grass, but be careful not to allow any to get on any other desirable broadleaved plants. One spray will usually do the job, though sometimes a second spray is needed in a couple of weeks.

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Is there a safe way to kill Cheat Grass without harming all the other grasses around it?

Answer: Probably the best way to get rid of the Cheat Grass without hurting surrounding plants is to use a preemergent type herbicide. A preemergent works by killing the seed of plants as they germinate. It does a great job on the seed, but has no effect on existing plants. Cheat Grass is an annual grass of a particular type called a Winter Annual. What the plant does is germinate from seed in the fall sometime (usually October or November) and over winter as a small seedling. Most people don’t notice them because they’re small and they often turn purplish, blending into the soil. As soon as it starts warming up (even a little bit) in February or March, the grass quickly grows, flowering and setting seed. By the time it starts getting hot, the plant browns and dries up, leaving seed to germinate the coming fall.

We have a pre emergent herbicide called Hi-Yield Crabgrass and Weed Preventer that has two preemergent herbicides in it which should do the job for you. You’ll want to apply it the first to the middle of October. It’s a granule that you apply with a fertilizer spreader and then be sure to water it in well immediately. The only potential drawback to using this product is if you have any other desirable annuals in the area you’d be treating it will kill those just as well as it will the Cheat Grass. If they’re spring germinating plants, they’ll probably be okay since the herbicide will probably have dissipated by then.

This product probably won’t kill 100% of the Cheat Grass but it should get rid of 80%-90% of it. Hope this helps.

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