157-How to Prevent Weed Overwhelm: A Practical Organic Approach for Real Results, With Margaret Roach

This week, I invited one of my longtime friends — and frequent podcast guests — to join me to share some additional weed management wisdom. Two weeks ago, the podcast touched on tools and techniques for battling weeds, and last week’s podcast was a reminder that a blanket of mulch can prevent many weeds from ever getting started. Well today, we explore how to prevent weed overwhelm with a practical organic approach for real results, with Margaret Roach. Applying her practice of a little good, old fashioned research and new-age-y mindfulness can elevate our skills against this eternal garden problem to a Zen Weed Master level.

If you aren’t familiar with Margaret Roach, allow me to introduce you. She’s a prestigious writer and podcaster, former Executive Vice President and Editorial Director for Martha Stewart Living, gardener extraordinaire, and she takes a mean photograph too. She lives on a 2.3-acre property in upstate New York, managing it to spectacular effect and largely on her own.

Margaret Roach has been cultivating her garden by hand for over 30 years. (photo: Courtesy Margaret Roach)

Out of necessity and natural determination, Margaret has mastered the art of accomplishing much with less effort. If there were a doctorate for overcoming overwhelm, she has earned it — thanks, in part, to her thoughtful and intentional approach to weed management

Like me, Margaret actually enjoys the task of weeding. There’s something about rhythmically moving from space to space, clearing away those unwanted botanical pests, that is meditative and satisfying. You might love it, or you might loathe it. Either way, it doesn’t take long for things to get out of control — even for the experts.

We gardeners tend to be an action-oriented bunch. We rush from project to project — planting, snipping, weeding, worrying, deadheading, mowing — the “ing” list goes on and on. Oftentimes, we whiz past a budding problem in our haste to get to the next thing on our list.

Margaret’s first piece of weed wisdom is that you break that habit and slow things down a bit. When you intentionally make time to observe what’s happening, you’re able to notice the little things before they become garden Goliaths. A pause as you move from here to there can be an opportunity to catch a weed in its early stages, while it’s much easier to address.

Know Your Enemy

Last month, The New York Times tapped Margaret to write a weekly gardening column. In one of her most recent submissions on weeds, she shared another typically sage piece of advice: Wise gardeners understand that we can’t successfully fight an opponent that we can’t identify.

Like all pests, weeds have evolved to be successful. Each variety has developed different survival mechanisms. Learn which weeds are finding their way into your landscape, and get to know more than just their name. Margaret compares them to heirloom plants — each weed has a history that might hold helpful clues. Be a curious gardener. How each variety grows and reproduces matters, because those qualities are your roadmap to overcoming that type of weed.

Hedge bindweed (Calystegia sepium) in bloom. Its cousin, field bindweed (Convolvulus arvensis), has a root system that can reportedly extend 20 feet underground. (photo: Margaret Roach)

Does the weed have a large taproot, rhizomes or roots that are shallow and fibrous? Knowing the answer to that question will help you understand which variety can be pulled out versus which weed you’ll need to dig up or thoroughly excavate to prevent future spread.

Does the weed spread seeds or have allelopathic qualities (more on that in a minute)? If so, your timing for removal is key.

A little research will also point you to which weeds are more likely to be hosts for diseases to which your desired plants are more susceptible. Chickweed is an example. More than various other weed varieties, the very presence of chickweed in your garden puts food crops like beets, turnips, cucumbers, and tomatoes at risk for the transmission of various diseases from weed to crop.

Margaret is a researcher at heart and owns more field guides than anyone I’ve ever known. Like an Army General, she has studied her weed enemies very carefully — looking for her best opportunities to beat them before they advance. By understanding the weeds’ lifecycles, she knows when to prioritize removal before the weed really gains a foothold, and she knows which method will save her time in the long run.

You can too, and you don’t need dozens of field guides to do it. I own four of them myself, but more often than not, I turn to some great online resources.

The UC Davis, University of Minnesota, and University of Missouri websites all offer good online weed identification tools. These resources walk you through specific questions to help you narrow down the list of suspects until you’re able to determine what you’re dealing with.

If all else fails, you can upload a picture of the weed in question to the iNaturalist app. There, it’s the other app users who will identify your weed culprit. Just remember to take any crowd-sourced information with a grain of salt. Glean what seems useful, but verify its accuracy.

Once you know the weed species, you can learn how it will try to spread. Let’s look at the weeds Margaret would call her top three thugs as an example:

• Mugwort – Through research, Margaret learned that this weed has a rhizomatous root system. If even a tiny piece of the rhizome is left behind in the soil, it will generate a new plant. The same is true of any rhizomatous weed species. Gardeners who don’t understand this might be inclined to give a quick pull on the foliage and assume it’s no big deal that some of the root material is left behind.

When you know that every piece of rhizome left in the soil is a future weed, you realize it’s worth a few extra minutes to get up as much as possible. It will save you a lot of time in the long run. Margaret has found that the best approach for these types is to gently loosen up the soil all around the roots, so the entire system can be teased out without breaking into irretrievable pieces.

One method for identifying mugwort (Artemisia vulgaris) is to check the underside of the foliage for its distinctive silvery tone. (photo: Margaret Roach)

• Oriental bittersweet – This invasive woody vine spreads by seed and strangles and kills shrubs and trees. Once established, it’s a beast to eradicate. Margaret has learned that this is an enemy best defeated at the earliest stages of growth. Birds eat the orange fruit the vine produces and carry the seeds in their bellies until they leave their “deposit” in your landscape. Three times each year — early spring, mid-summer and fall — Margaret designates a specific time to go on “bittersweet patrol” seeking out young Oriental bittersweet seedlings.

More often than not, sprouts are gathered in large numbers under trees and shrubs where the birds have perched in the branches. By pulling the young seedlings, Margaret is saving herself from having to tackle tough mature vines (and more seed-bearing fruit) in seasons to come.

• Garlic mustard – This is one of those pesky allelopathic weeds mentioned earlier. It exudes a chemical through the soil, preventing germination of other plants. In other words, the plants you want are hindered from ever getting started. Garlic mustard also flowers and sets seed — which can remain viable in the soil for more than a decade. That makes it a double threat in Margaret’s garden, so she makes this highly invasive pest a priority for removal in spring. She doesn’t allow it time to affect other plants or to set flower.

One of my worst weed foes is hairy bittercress. It’s another member of the mustard family of plants. This plant is a nightmarish marvel. Its flowers mature into silique  — long seed pods. Correction: long, exploding seed pods. Once the seeds have matured, the slightest touch to the pod initiates the plant’s ballistic dispersal strategy. The seeds literally explode from the pod — launched up to several feet away from the mother plant.

Hairy bittercress is not a perennial plant. The parent plant lives just one season or two at most. The only way this weed remains a problem is if it is allowed to go to seed, Knowing this, I can keep it — and any other seed-spreading weed — under control by removing it before seeds form. Even if I only have time to mow or cut the foliage down, preventing a seed head defeats the weed.

You’ll also be much better off if you learn to identify what your area’s weeds look like at various stages. By the time a weed fully matures, it probably has already gained a solid foothold. Beat it to the punch by becoming familiar with how to spot the weed seedlings among your other plants. Margaret loves using the University of Chicago Press book, Weeds of North America, for just that. The book doesn’t include every species for our continent, but of those it does include, there are pictures showing every life stage.

These young Oriental bittersweet (Celastrus orbiculatus) seedlings might seem benign, but they will mature into a vine that is difficult to control and notorious for strangling trees and shrubs. (photo: Margaret Roach)

Stay Focused

If you’ve ever felt overwhelmed by weeds, take heart. You’re in good company.

I’ll admit that when I’m weeding a bed, it can be so easy to get distracted by a shrub branch I notice needs pruning or a bare spot needing some fresh mulch. Yet, I’ve learned over the years that a do-everything-at-once approach leaves me feeling like I never really made any headway at all. These days, I make a point to assign myself pruning time, weeding time, etc; and I focus that time on that particular task.

While on “bittersweet patrol” Margaret will remove other weed varieties she comes across, but she keeps herself focused on attacking Oriental bittersweet as the priority. The same is true when she goes on springtime garlic mustard patrol or sets her sights on any other one task for a day.

Since we don’t allow ourselves to deviate from our goal, we accomplish more of what we set out to do. That focused approach keeps overwhelm at bay.

Once you’ve gotten to know your weeds, try keeping your efforts focused for an afternoon — or even just 30 minutes — on just one priority. You’ll feel better about your progress at the end of the day.

Margaret keeps things under control by applying focus in another way throughout the season. She makes a quick pass through each of her eight landscape beds once a day. In a half hour or less, she keeps things under control by catching any newly developing weeds while they are young and easiest to remove.

This Gallant Soldier weed (Galinsoga ciliata) is an annual plant that will die at the end of the season. So, it can be controlled by cutting back foliage before it has a chance to set flower. These blooms on will mature into seeds that mean more weeding time for you in future seasons. (photo: Margaret Roach)

Other Considerations

Another pro tip when it comes to weed removal is to make the most of a rainy day. Moisture softens the soil, so it’s easier to extract plant roots. The day after a rain is the best day to do a little weeding. If there’s no rain in the forecast, weed after watering. Whatever you do, avoid weeding while the soil is dry. Pieces of the root are more likely to break off and remain to produce more weeds.

I refer to myself as a “down & dirty” weeder. I get right down in there with the enemy, sprawling in every direction to reach as many weeds as possible. Being in the thick of things is also how I notice things that I would likely miss otherwise.

I’ll admit that approach got me into trouble once. I was so focused on the weeds that I didn’t notice a protruding branch until it poked my eye. Now, I make a point to wear eye protection, and Margaret recommends the same. It just takes a moment and one wrong move to cause serious injury, so be smart and protect yourself.

Your own two hands are your best tools for weeding but consider adding these handy items to your arsenal as well:

• Hori Hori knife or soil knife – Margaret and I both love this tool. I use a soil knife to dig up tap-rooted weeds. Margaret would be lost without her Hori Hori knife to help pry roots out of crevices around her property.
• Winged weeder – This tool is perfect for slicing shallow-rooted weeds right at the surface of the soil. I can clear a 10’ space in less than a minute. I firmly believe it’s the only successful weeding that can be accomplished while standing up.

Margaret and I both avoid using weed treatments — even organic options. It’s important to remember that not all “natural” products are benign. After all (as friend and horticultural expert Dr. Jeff Gilman says), snake venom is natural too, right? Horticultural vinegar is a prime example. Sure, it’s organic, but it’s acetic acid — at 20% strength! This stuff can be dangerous to your health, and it’s certainly lethal for many of the beneficial creatures in your landscape.

These treatments rarely kill the weed either. As we discussed in the podcast two weeks ago, they kill the foliage but rarely the root. If the roots live to see another day, so does the weed.

Margaret will use a Hori Hori knife to help her remove weeds growing in cracks along her walkway – like this clump of garlic mustard (Alliaria petiolata) seedlings in a crack by the walkway. (photo: Margaret Roach)

The most effective (and safest) way to apply horticultural vinegar or other weed treatment is to apply it very precisely and while wearing appropriate protective gear. Margaret gave the example of her Oriental bittersweet nemesis. Rather than hose that sucker down with treatment with a “the more the better” approach, she cuts the vine and applies a few drops to the cut end. That gets the treatment directly into the system of the plant and prevents unintended consequences. This is a great approach for treating poison ivy too.

Weeds in Compost

Gardeners often ask me if weeds can be composted. As a general rule, I recommend against including weeds that are diseased or have gone to seed. The compost may not remain hot enough for long enough to kill the disease or the seeds. Margaret uses a passive compost system, so she takes additional precautions.

Rhizomatous weed pieces would be inclined to regrow in a compost heap — particularly in a passive system. So, Margaret gathers those into a large plastic bag, closes the bag and places it in a sunny area. Over the course of a few days, the air temperature in the bag gets so hot that the weed tissue is cooked to death and the seeds are rendered unviable.

With some weeds, Margaret makes time to cut off the problem portion of the plant (like a flower maturing into a seed head and the roots) and throws those parts out. The rest of the weed can be safely added into the compost.

The approach you take should depend on the type of weed you’re dealing with, how you maintain your compost heap, and how willing you are to risk reintroducing weeds or disease when you amend compost.

Hopefully, you noticed that this episode (and the two prior podcasts) doesn’t tell you how to eliminate weeds completely. Neither Margaret nor I have the perfect, weed-free landscape. That’s just an impossible goal.

The imperfection of it all is one of the many things I love about gardening. There’s always room for improvement — a new challenge to overcome. If I felt I had everything under complete control, it just wouldn’t be as satisfying. I hope you are able to embrace imperfection in your garden too.

This mature garlic mustard is allelopathic. A chemical it exudes into the soil will prevent other plants from germinating. (photo: Margaret Roach)

I also hope you’ll be sure to listen to my conversation with Margaret by scrolling to the top of the page and clicking the Play icon in the green bar under the page title. Margaret always offers a thousand snippets of sage advice, and this week is no exception. For example, she reminds us that not all weeds are actually weeds. Some — like Joe Pye weed — are important natives and hosts for beneficial insects.

So, which weeds are always seeking to get the upper hand in your garden? I hope you’ll share your challenge and observations in the Comments section below.

Links & Resources

Episode 015: Life Lessons on Gardening and Design with Margaret Roach

Episode 020: Gardening for the Birds with Margaret Roach

Episode 065: Tips For Reducing Garden Overwhelm, With Margaret Roach

Episode 080: Putting the Garden to Bed: End-of-Season Advice from Margaret Roach

Episode 101: A Way to Garden: Observations and Lessons, with Margaret Roach

Episode 120: Poison Ivy: What You Need to Know to Minimize Its Impact on You and Your Landscape

Episode 124: Using Compost the Charles Dowding Way: More Than Just a Great Soil Amendment

Episode 155: Managing Weeds Organically: Rodale Institute’s Latest Research, Prevention and Control

Episode 156: Encore Presentation: Why Mulch Matters in Every Garden: What You Need to Know

joegardener Online Academy  Three popular online courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!

joegardener Online Academy: Master Pests, Diseases and Weeds – Just $47 for lifetime access!

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Growing a Greener World® Episode 418: Garden with Margaret Roach

Growing a Greener World® Episode 526: Backyard Birds

Margaret Roach: AWaytoGarden.com

The New York Times: In the Garden

iNaturalist

Weeds of North America, by Richard Dickinson

UC Davis: Weed Research & Information Center

University of Minnesota Extension: Weed Identification

University of Missouri: Division of Plant Sciences: Weed ID Guide