Creeping Spurge, Dandelions and Crabgrass
Wed, 5/19 ยท 10:19 AM
Taun Beddes
0:00
I wanted to put out a quick apology for missing an episode last week. I've been extremely busy. And part of last week I was under the weather. So thank you again for your patience and thank you for listening.
TB
Taun Beddes
0:11
Hello and welcome back to the homegrown horticulture podcast. On this week's episode: lawn weed control.
TB
Taun Beddes
0:19
The homegrown horticultural podcast is specifically for the Intermountain West areas like Denver, Reno, Salt Lake City and Boise, and all points in between. We have unique soils and a unique climate like nowhere else in the United States.
TB
Taun Beddes
0:35
Several years ago, I worked for a large retail nursery, and one of my responsibilities was helping landscape contractors. One particular landscaper used his home as a showpiece where he would show them everything he could do as a landscape contractor in an effort to land the bid to install their landscape. One thing that this contractor really prided himself on, was his great looking lawn. For a long time when you looked at it, it was totally green, perfectly manicured and there wasn't a weed in sight. After a few years, the lawn started to turn yellow and have other problems and nothing that the contractor did seem to fix the problem. I was sent by the nursery to take a look at the lawn and I found that it was being mowed about an inch and a half high water daily and fertilize six or seven times a year. I told the landscaper to water a couple of times a week deeply raises more blades up to two and a half to three inches and to cut his fertilizer applications in half. I don't know if he ever did or not. He wasn't very pleased with my answer.
TB
Taun Beddes
1:43
But my reason for telling this story is to introduce the topic of reasonable lawn expectations contract contrary to the belief of many, it's just fine to have a few weeds in your lawn and a few brown spots, especially with our drought situation in many parts of the West. So very briefly, some things you can do to maintain a healthy lawn is to mow at a height of three inches. I know the grass can be a little bit more Shaggy, but it allows the roots to grow more deeply and allows the grass to become more drought tolerant. Additionally fertilize on an as needed basis and not on a calendar. Most lawns in the Intermountain West will survive just fine being fertilized two to three times a year. That would be once in the spring once in late summer and once in late fall, trying to time that last application with a rain or snow storm between mid October and early November. As far as irrigation and an average loamy soil. You should be irrigating once to twice a week over your lawn so that water penetrates into the soil about six inches to a foot deep, heavier clay soil should be watered more often but with less water because the water doesn't penetrate as deeply into the clay. Likewise with sandy soils, you should water more often but with less water because they're so well drained. Water easily penetrates to a depth of six inches to a foot and so add water three to four times a week. Just like keeping our own bodies healthy. Maintaining your lawns correctly, will maintain the lawn health and reduce the number of weeds that actually can invade the lawn. There will always be a few but these will be easily pulled by hand or popped out with a screwdriver or something. And it's usually the overly maintained lawns or under maintained lawns that are more susceptible to weeds which is going to be today's topic. Keep in mind also that healthy lawns that are mowed high, shade out weeds and crowd weeds out because the lawn is so thick.
TB
Taun Beddes
3:48
The first weed I want to talk about are dandelions. They are native to Europe and Asia but have become established worldwide. there either by annual or short lived perennial and mainly bloom in the spring. Although they can sporadically bloom through the summer as I watch social media. A lot of people actually do not consider these weeds because they're edible and they're utilized by pollinators, especially honey bees, and especially in the beekeeping crowd every time I see a post on Facebook about people saying how do I control dandelions. There's several people that comment. These aren't weeds, leave them alone, the pollinators are struggling, just put up with them. And then there's the other crowd that considers these a weed and has no problems removing them.
TB
Taun Beddes
4:39
Personally if I have a few in my lawn or a few in my garden space, I don't consider them weeds. My daughter likes to pick the flowers. And in a way I think they're kind of pretty, but when they start to get really excessive, I will go ahead and control them. Now my first defense against dandelions as we mentioned earlier is a healthy lawn Number two is just a simple dandelion digger, I can get from the hardware store for between three and $5. They work really effectively and you can pop a couple of dandelions a minute. And so if you only have 15 or 20 in your lawn, you can probably have them out in just a couple of hours. For extreme situations, I will use a lawn weed killer. There are several brands available and you don't need to spend a lot of money. We like to spray them in the spring, but they're actually best sprayed out in the fall because the poison goes down to the root and you get a better kill before they go to flower and spread more seeds.
TB
Taun Beddes
5:41
The next weed on the list is prostrate spurge. Prostrate spurge, is an annual that germinates when soil temperatures are between 50 and 60 degrees. We don't notice prostrate spurge as much in the spring because it focuses its energy and efforts on sending down a long taproot so that you can grow during the middle of the summer. And with this long taproot and other adaptations, it's quite drought tolerant. And so we really start to notice it in late June into July because these adaptations allow it to outcompete lawns that are not maintained correctly, that really starts to get aggressive and flowerbeds and gardens during the same period of time.
TB
Taun Beddes
6:23
Another reason you may see it show up unexpectedly is because a few plants can produce 1000s of seeds and within just a couple of years, it can take over an entire area. Out of fear of sounding like a broken record here. The best way to keep this out of your lawn is to maintain a healthy lawn. If it does get loose, then as quickly as possible try to fix the management problems with the lawn so you can suppress the weed from spreading further. And so if you found it in your lawn, one of the best methods of control includes herbicides in the spring if you apply a pre emergent for crabgrass. Most of these pre emergent products will also help suppress prostrate spurge. There is a particular preemergent is not as commonly used on lawns that's really good against broadleaf weeds like prostrate spurge. It is Isoxaben. I used to be sold under the brand gallery or Galleria. As far as the homeowner market, I currently see it sold by the company formerly known as Bayer who changed their name to BioAdvanced. Their product is called "Season Long Weed Control for Lawns.
TB
Taun Beddes
7:35
A problem that we often run into though with spurge is that we don't see it until July. And if you want to use what's called a post-emergent herbicide that would be something like a dandy lion killer in the middle of the summer it is just flat out too hot to use them. Temperature restrictions vary on these particular products from 80 to 90 degrees, where it is too hot to use them but in the middle of the summer. Even if you apply at night or early morning when it's below these restrictions, I still see that there's potential for them to vaporize and drift in the air and potentially damaged desirable plants that are adjacent to where you sprayed. There are potentially a few lawn weed killers that could be used in the middle of the summer, but I hesitate because they do have some restrictions that other more common lawn weed killers do not. If you have questions about these, contact me through the Homegrown Horticulture page on Facebook where we can answer questions.
TB
Taun Beddes
8:33
As I mentioned earlier, prostrate spurge is not exclusive to lawns but is also a common weed and flower beds and gardens. There are actually some expanded control options in these areas. The first pesticide free method I want to talk about is cultivation. This involves mechanically severing the roots from the top of the weeds using something like a gardening hoe. It needs to be done weekly but can be very effective.
TB
Taun Beddes
9:01
The next control method is mulching. Plant based mulches are the most common where they're usually made of something like ground up, chipped, or shredded bark. Especially in vegetable gardens, grass clippings are also very common. These should be applied before the weeds come up or just after you finish cleaning weeds out so that they can suppress any further germination.
TB
Taun Beddes
9:24
One caution with grass clippings is that you do not want to put them in your flower beds or your garden if they've recently had a pesticide applied to them especially something like weed and feed or a dandelion killer. If you have applied such things, consult the label of whatever was applied for specifics on this.
TB
Taun Beddes
9:41
One final method that does not involve use of pesticides I will mention but with a lot of caution is burning the weeds using a weed torch. Weed torches can be purchased for anywhere from about $50 to $100 from a local hardware store or online. A lot of people think that they might be fun to use and they can be, but you really have to be cautious with these. They're only really effective against weeds that are less than about an inch and a half tall. Much taller than that and you will burn the leaves off the tops of the weeds, but it doesn't get down into the crown, and the weeds just regenerate. Another caution about these is that because you're playing with fire, if you're spraying weeds in an area where there's a lot of dead undergrowth or dead weeds underneath, it will start those on fire too. And it's really common for these to get out of control. One of our major wildfires last year, it was actually started by somebody using a weed torch. Another precaution includes do not use a weed torch on top of bark mulch. The bark mulch, if it's extremely dry could also start on fire.
TB
Taun Beddes
If you choose to use chemical controls in your flowerbeds to prevent spurge, the best option includes pre emergent products. Pre emergent products control weeds as they germinate as they send their little root out before the leaves emerge on top. The active ingredient in the pre emergents prevents that root from growing and then the little seedling just dies. The pre immergent branded Preen is extremely common for both flower bed and garden use. But if you look at the label, prostrate spurge is not included in the weeds that preen controls. The off brand or oftentimes the storebrand version of Preen called treflan, tr e f l a n. It also does not include spurge as a weed that's controlled on the labeling. They're not as popular as Preen, but especially garden centers and farm stores carry other pre emergent products that are registered for use at least in flower beds. Oftentimes not gardens though. I f you choose to use these spurge is often listed as a weed that will at least be suppressed just make sure and follow the instructions on the label to avoid getting into trouble. If there's enough space in between plants and you choose to you might be able to use a glyphosate product such as roundup in your flowerbeds or garden to remove the newly germinated weeds. I don't really recommend it because you never know when you're going to mess up. But follow the label and you may have to cover the plants if you choose to. But I just wanted to put out there it is an option.
TB
Taun Beddes
The next weed on the list is crabgrass. There's lots of confusion about weedy grasses to where oftentimes we just call every weedy grass crabgrass or barnyard grass to where there's actually several species that infest our lawn that look quite similar, but control options for these grasses can sometimes be quite different. And so if you already have weedy grass in your lawn, it's most likely not crabgrass unless you live in the St. George area or other extremely warm areas.
TB
Taun Beddes
Crabgrass germinates when soil temperatures are between 50 and 60 degrees, and like spurge it doesn't really rear its ugly head until late June and July. And it's usually at its worst through August and September, and then it's killed out by hard frost. So crabgrass is what we would call a summer annual to where it germinates in the spring and dies in the fall. Knowing this lifecycle is very important because it helps us actually control the grass and our lawns. I'll repeat before I get into chemical controls that maintaining a healthy lawn will do a lot to fight against crabgrass, depending on your particular location. There are several brands of pre emergent weed killer, they're specifically branded for crabgrass. They include such brands as Pre M, Dimension and B arricade, but there are many others out there. They should be applied when the bush forsythia is in bloom. Those are the big yellow bushes you see in early spring and that's generally good timing to get that pre emergent applied. Follow the instructions on the bag. These pre emergent products are often bundled with a fertilizer, thus making it possible to multitask in early spring. Right now, most listeners are going to live in areas where forsythia has already bloomed. And it's too late to put down and pre emergent. It is still cool enough in most areas to apply a lawn weed killer. If you're going to there are some out there that will have some post emergent control of crabgrass. They will say something like Ortho Weed B Gone with crabgrass control, or weed and feed with crabgrass control. The active ingredient in these products is quinclorac, which is also quite effective against many other weeds. At this point, if you do suspect you have crabgrass germinating, then these would probably be effective at least at suppressing it.
TB
Taun Beddes
Well folks, I think I'm going to call this an episode I have some more weeds I want to talk about but it will have to wait. Thank you again for listening and I will talk with you next week.
TB
Taun Beddes
The homegrown horticulture Podcast is a production of Utah State University Extension show music was written by Savannah Peterson, a Utah State University horticulture assistant and talented artists. Thank you to her. Thank you again for listening
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