Category Archives: Weeds

How To Identify Weeds in Your Garden

Identifying weeds might not rank up there with ridding the garden of the invaders, but it often drives me mad when I can’t identify a weed. It’s more important to know a weed from a desired plant or wildflower, so you know whether to leave it alone or destroy it before it spawns and takes over your garden.

So, how can you tell a weed from a flower? Here’s a definition I received from a weed scientist with New Mexico State University in their master gardener training materials: “A weed is any plant that interferes with the management objectives for a particular site or situation.” That’s actually a brilliant definition (must be because he is an expert). Here’s why:

One gardener’s weed is another gardener’s favorite fauna, but with some caveats. In other words, if you love dandelion flowers and want to leave them in your garden, then maybe dandelions are not a weed. If you leave purslane to grow because it’s an edible weed (as are parts of the dandelion), then more power to you. But if the purslane begins to cover your thyme or the dandelion chokes out the small area of grass you have in your lawn, do you shift them into the “Weed” column?

mexican hat

Mexican hat (Ratibida columnifera) seeds all over our garden. It’s a fun summer flower, but was recently host to what looked like baby cucumber beetles. It also grows tall and blocks sun and air from getting to nearby plants. I pulled a bunch of them.

Another way to look at it is to peg a weed according to some criteria set by the Weed Science Society of America. According to their site, weeds have common characteristics, including:

  • Production of way more seeds than normal – up to tens of thousands from a single plant.
weed seeds in garden

No, we didn’t scatter feathers on the ground. Those are weed seeds, in a bed we worked on at least twice. There’s also an elm tree sprouting — extra credit if you spot it.

  • Long survival time for seeds, which can remain dormant in soil until just the right weather or other condition triggers growth.
  • Rapid establishment (yes, they really can crop up nearly overnight).
  • Mechanisms that support easy spread.
  • Ability to grow in places where other plants can’t, such as between rocks or in poor, dry soil.
field bindweed

Field bindweed, aka wild morning glory. Sure, give it a pretty, regular name. It grows anywhere, and especially loves rocks AND rose trunks so it can hide before it chokes the life out of the poor rose.

If you look at the one attribute that all of the points above have in common, it’s this: survival. I can’t count how many times we’ve sowed some flower or vegetable seed at just the right depth, watered it regularly and checked daily. Nothing. But weeds – they keep returning for encores, even when you try to destroy them!

Aside from persistence, the ability to outcompete nearly any plant and your best efforts to remove it, there are a few other ways to tell  a weed from a regular plant when you’re examining it in your garden. For example, the characteristics that help weeds spread their seeds might show in their appearance. Hooks, spines and stickers make them harder to pull. And some have adapted attractive flowers to fool gardeners. A tap root often is a sign of a weed, or at least a plant’s survivability. You can pull and pull, but if you break the root off, it comes back and is somehow stronger than ever. Rhizomes or stolons also help weeds spread just underground, especially grassy weeds. And some weeds have asexual properties so that they can reproduce plenty of new plants with no floral fertilization.

dandelion in gravel

Dandelions have telltale spiny leaves, a tap root and lots of seeds after flowering.

In short, if a plant is wrapping around another plant, cropping up on, under or around a plant so that it affects your desired plant’s ability to use sun and water, call it a weed. We have some gorgeous volunteer wildflowers that come up each year in our garden, but we don’t keep all of them. If they crowd out another plant or cause so much shade around roots that a rose gets fungal during the monsoon season, they’ve got to go. I’ll keep a few of them, which means I’ll have to thin again in the future. But I won’t call them a weed.

I’ll post some of the worst New Mexico offenders in the future. For now, if you need help identifying weeds, check out the tool and external links under the WSSA’s Weeds section on their menu. I’ve also posted some new links on my Resources page.

Social Media Memes: Gardening Fact or Fiction?

Call me a skeptic. It’s OK, because I am one. I always have been. And I prefer to investigate claims, especially those I see on television or social media. The more often I see a social media gardening claim, the less likely I am to believe its validity.

When I write posts for Gardening in a Drought, I use my personal experience, master gardener training and lots of other sources – books I value and credible websites. If I’m uncertain about a site’s credibility, I always try to verify the information. And most of the information I rely on comes from university extension offices. They’re the source for research-based advice for farmers and homeowners. When it comes to growing food in particular, I’ll take research over pins and “likes” any day of the week.

Don’t get me wrong – I love social media platforms! But I use social media to generate ideas and avenues I want to explore. I don’t consider a post or pin originated by a virtual stranger to be the expert word, the final say. And even posts and pins from more credible sources can be problematic. For example, an article might tout the “Best perennials for shade,” but have its origin in a Georgia newspaper. The rainfall and soil in Georgia differ markedly from here in New Mexico. I need a list a little more specific to my conditions. And that’s just one of the problems I have with some of the social media memes and myths. Here are a few examples:

Epsom salt

This is the biggest meme of all. When my husband and I discussed that the entire Epsom salt craze must have been started by savvy Epsom salt marketers, I felt ashamed, as if my jaded skepticism had reached a new low. And then I just felt vindicated (so much sweeter). First, I found a pin touting the miracle “salt,” which is really a mix of mostly magnesium and sulphur for soaking feet, as a way to make “all of your blooms more vibrant, healthier, greener, thicker, etc…” Can I just add an editor’s aside here? There is hyperbole, and then there are errors in use of adjectives. Well, I guess it is an error only if you have a bloom color other than green. And right now, I cannot think of a plant with green blooms…

OK, sorry. The pin to which I referred linked to … you guessed it … a company that sells Epsom salt. And the product now lines the walls of the local Walmart when you walk inside. What a racket! I have decided to begin touting the benefits of yellow alyssum seeds “to make tomatoes juicier, redder, rounder and larger.” I could make them greener too, I guess.

bag of Epsom salt

Tim bought a bag of the salts to try to help get rid of some tree stumps. It didn’t really help, and I kept thinking: How could something that kills tree stumps be good for tomatoes?

Anyway, the truth is this: Epsom salts really do nothing for any plant or soil in your garden (link to my Resources page for a few sources). If you have super-acidic soil, which is uncommon anyway, it would be better to amend the soil with dolomitic lime than with Epsom salt. And it certainly is not the way to go in New Mexico, where soil tends to be alkaline. In fact, Epsom salt can do more harm than good.

Household vinegar kills weeds

I’m guilty of picking up on the household vinegar meme. And even household vinegar can weaken weeds to some extent. But the truth is, for vinegar to be truly effective on weeds, it needs to be 20 percent acetic acid. This is not your typical household white or apple cider vinegar.

What you need to really achieve control is the higher concentration acetic acid vinegar solution that is approved for use as an herbicide. It is available commercially in some formulas and from certain local or state agencies. We filled about 10 gallon-jugs at the Upper Hondo Soil and Water Conservation District office a few weeks ago and used their formula to mix it with water and dish soap.

For the most part, the acetic acid weakened, or at least stopped the growth of, many weeds. It’s not selective, however, so if you target a dandelion in the grass, you get dead, brown grass around it if in the spray. In addition, vinegar isn’t a systemic herbicide; in other words, it kills leaves but doesn’t work down to the roots. But I think the acetic acid solution can work well in gravel walkways and along rock walls or paver edges, the areas where grass and weeds poke through. Spray on a warm, sunny day and repeat again as needed. If you want to try the household vinegar on small weeds, you might have some success, but it’s probably better mixed with baking soda as a cleanser!

weed killed by acetic acid

The acetic acid formula really did destroy or weaken some weeds, but notice the bindweed peeking into the frame. Of course, I am not sure if anything can kill bindweed.

Use of corn meal to stop weeds from geminating is another myth based on a similar, but commercial product. The bottom line? Take social media advice with a grain of, well, salt. And always check to see if it’s accurate and pertinent for your garden soil and climate. Your best sources are local master gardeners and extension offices, or the best gardeners on your block!

The Good, the Bad and the Ugly: Weed or Wildflower, Part 2

Nearly a year ago (in May 2014), I wrote a post about the fine line between weeds and wildflowers. The gist of the rant was that our rock garden and entire property was being invaded by a lovely flower called yellow alyssum (Alyssum alyssoides). It’s a little earlier in the spring, and even yellower!

First, the good. If you love early, yellow blooms, this is a pretty little flower. It looks pretty up against a rock or under a red rose, perhaps. Notice I said “it,” as in a single plant. More on that in the ugly portion…

yellow-alyssum

Yellow alyssum sprouting from rocks in a New Mexico rock garden.

Now for the bad: This little spreader has cropped up throughout the garden, and we’ve pulled up a few, though I surrendered long before my husband. He has much more patience, though he hasn’t yet tackled the entire garden. Because he wouldn’t get halfway before he had to start again.

alyssum-prickly-pear

Yellow alyssum growing between pads of prickly pear cactus.

If I had any doubt last year about alyssum’s classification as a weed, at least in this setting, I have no doubt now. And that’s the ugly part. Despite our best (nontoxic, of course) efforts to control this little bloomer, it has taken over every nearly every surface and begun spreading to neighbors’ lawns as well. I have no idea how it started; it came with the house!

alyssum weed

Yellow alyssum as invasive weed in southeastern New Mexico.

Having called it ugly, I have to admit the lawn is really pretty when the sun hits it just right early and late in the day. And we are doing our part ecologically, because the bees swarm all over it when the sun shines. The dogs and deer must tread carefully.

alyssum and deer NM landscape

OK, I admit that the alyssum looks pretty here from a distance. But play “Where’s the Alyssum?” and you’ll spot it everywhere. And what exactly are those deer running from?

As for last year’s fear about the alyssum choking out summer grass, we still had a green lawn come summer. We don’t know if the flowers delayed the grass coming in, but I have a feeling they did. And I am frightened to think what will happen as it takes over, reseeds and multiplies. Meanwhile, I need to research medicinal properties of alyssum flowers or something. Maybe I could make some money?

UPDATE April 6, 2015: A few days after posting this, we headed east to visit relatives, through Roswell and almost to the Texas border. Guess what we saw growing in the worst possible conditions along roadways nearly the entire trip? You guessed it! And it was in my in-laws’ lawn and their neighbors’ yards too. My mother-in-law said she has seen it for years and knew it as a prairie wildflower. I give up and accept this invasive plant as a prairie wildflower … for now.