Home Gardening preventing weeds: an all-season strategy, with mt. cuba’s duncan himmelman

preventing weeds: an all-season strategy, with mt. cuba’s duncan himmelman


‘THERE’S ALWAYS a weed on the market, irrespective of when. That’s what in the present day’s visitor, schooling supervisor Duncan Himmelman of Mt. Cuba native plant heart in Delaware, stated the opposite day on the telephone. And which means now, whilst we strategy the quiet season, weeds are lurking, and we have to know when and methods to goal our efforts to manage them.

Duncan Himmelman, at present the schooling supervisor at Mt. Cuba Center, a renown native plant backyard and analysis website, earned his doctorate in decorative horticulture at Cornell earlier than educating school for 24 years. He’s additionally managed a big non-public property and designed gardens for personal purchasers, so he is aware of from weeds and weeding.

We talked about weed ID, and why it issues to know a weed’s title and life cycle (that’s chickweed, Stellaria media, a winter annual, above; photograph from Wikimedia). We additionally mentioned removing techniques and why skipping the chemical substances makes the very best sense, and extra.

Learn alongside as you take heed to the November 2, 2020 version of my public-radio present and podcast utilizing the participant beneath. You may subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here).

mt. cuba’s 6 new digital courses on demand

A COURSE on weeds is one among a half-dozen on-demand recorded programs Mt. Cuba is at present providing to the general public (extra on that beneath, within the transcript–or browse them now). Enter to win a ticket (on me!) to the course of your alternative by commenting within the field on the very backside of this web page.


all-season weed management, with duncan himmelman



Margaret: Seen any weeds but this morning, Duncan? [Laughter.]

Duncan: Properly, no, I’m averting my eyes. No, they’re in every single place as .

Margaret: So we should always say to everyone that what acquired me alerted to your weed course—effectively, what acquired me alerted to the truth that you had been into weeds and educating a course on weeds really, which is one among the recorded courses at Mt. Cuba that folks should purchase on demand—was that I acquired a press launch about this entire collection of digital courses.

The courses are an awesome useful resource; you guys have nice in-person occasions when the world permits and so forth as effectively. However I questioned for those who might simply inform us about this providing of digital courses on demand.

Duncan: Yeah. As , when COVID struck, we hadn’t achieved any on-line schooling. And so we needed to rapidly pivot to transition our courses that had been going to be reside and in-person to on-line. And on account of that, we document every class and the recordings have been filed and a few of them have been saved for resale, as you talked about, as recordings in our classes-on-demand choice. And there are six of them: One is on soils. One is on the very best native crops for containers. There’s one on monarch butterflies, a butterfly backyard, and groundcovers, and weeds.

Margaret: Sure, it was nice since you guys, I imply, I all the time love speaking to anybody on the employees there and I learn so much, so I used to be so excited to see and to have the ability to share.

In order I began at getting right down to enterprise, as a result of we acquired to do some weeding, Duncan. As I stated at the beginning quoting you, “There’s all the time a weed on the market, irrespective of when.” So what’s a weed? Let’s simply rapidly begin there earlier than we get to techniques.

Duncan: Yeah. Typically it’s outlined as one thing that’s rising in a spot the place it’s not needed; that technically it’s misplaced. In that sense, it might be something from frequent dandelions, as all of us effectively know, as much as even a small shrub that’s planted within the mistaken location in your property. Not that folks would take into account {that a} weed within the sense that we sometimes do, however yeah, it’s basically a plant that’s rising the place it actually isn’t needed.

Margaret: Proper. And the issue with these is that they compete towards the needed crops, proper?

Duncan: Yeah. I imply, all crops are taking over water and vitamins within the soil, and they are often limiting. So weeds are taking those self same water and vitamins for themselves, on the expense of the crops that you simply actually need in your backyard. So yeah, competing for assets is without doubt one of the ways in which weeds are profitable.

Clearweedm or Pilea pumilaMargaret: So simply to be clear, I imply, Mt. Cuba is that this well-known and fantastic native plant heart—a spot of schooling, a spot of analysis, and so forth. Not all weeds are aliens, i.e., non-native. There are “native weeds,” quote unquote, and there are generally native crops which are within the mistaken place; they’re just a little too formidable.

So it’s not “that’s an alien and that makes it a weed,” proper? I imply, we’ve got clearweed, Pilea pumila [above], I believe it’s referred to as, jewelweed, and pokeweed. They even have weed of their frequent names, some conventional native crops which have nice wildlife worth, too, however perhaps the gardener sees them as a weed in sure spots.

Duncan: Yeah. The best way our gardeners handle the panorama is to edit out crops which are going to be, as you stated, too rambunctious or too aggressive. So we do have pokeweed on the property and it may be very… it will probably seed in pretty prolifically and it’s a perennial and it’s tough to eliminate. However they do go away the odd one right here and there as a result of it’s native and so they do present ecological companies which are fairly necessary. So yeah, not all weeds within the sense that you’d outline them are alien.

Margaret: Yeah. I don’t know if you’re a field-guide nerd like I am, however I’m. I’ve an entire cupboard stuffed with discipline guides, and quite a few them are about weeds. And I really like figuring out the names of my weeds. I really like having the ability to ID my weeds. Within the class on weeds, do you encourage individuals to get to know them by their correct names?

Duncan: Sure. I imply, I come from a protracted line of a few years of educating, and it’s all the time finest to show the scientific title of the plant as a result of that’s the bonafide title that follows that plant oh, from nation to nation, from state to state, and so forth. So yeah, I’m all the time very vulnerable to utilizing the scientific title once I speak about weeds and different crops generally. So I’ll generally stumble over the frequent names as a result of I’m not as used to utilizing them.

However we give each of them to our college students and we emphasize the truth that if they’ll really study the scientific title of those crops then they’ll do their analysis on-line in a simpler method.

Margaret: And I’m going to offer some hyperlinks, a few of which you shared with me and a few that I exploit myself, to some online weed ID resources from varied universities across the nation and so forth that folks could discover helpful for studying some primary ID, and in addition to some information books and so forth [links at bottom of page].

In order that will get me considering, talking of the correct title of chickweed, Stellaria media is how I say it [photo top of page]; I don’t know if that’s proper. However I used to be exterior this week in my backyard and on the edge of 1 giant mattress, there have been plenty of little chickweed crops. Now, what the heck is it doing as winter approaches, seeming to begin to develop? [Laughter.]

Duncan: Yeah, I do know you’re considering of that weed season is over.

Margaret: What’s occurring?

Duncan: It’s heading into winter and we don’t have to fret about weeds anymore, however as , weeds don’t take any day without work. With Stellaria, chickweed, what you’re seeing is little rosettes or little seedlings arising right now of yr. And the explanation they’re arising is as a result of it’s cool and moist, and these are the best sorts of germinating circumstances for what we name winter annuals.

And it type of will get again to your earlier remark about why are they arising right now of yr; we’re heading into winter. So they may germinate now. And there’s quite a few these winter annuals that can present their heads at this second and they’re going to stay inexperienced on this vegetative state all through this a part of the season, go dormant, after which in early, early spring, when winter is simply subsiding, they’ll begin to flower. So these winter annuals, like chickweed, will bloom early within the spring. And I believe individuals have seen that, that, wow, right here’s this plant, it’s very early, it’s like April, what’s occurring, it’s already flowering? However it’s been sitting there, dormant, within the leafy stage over the winter. So yeah, that’s what’s occurring. There’s an entire bunch of this stuff referred to as winter annuals.

Margaret: Yeah. So it appears to me that it’s going to be lots simpler to reckon with these little guys than who they’re going to change into by April or later, sure? So, I imply, this offers us some tactical hints, figuring out the life cycle, figuring out that it’s a winter annual, proper?

Duncan: Yeah.

Margaret: So is {that a} technique then that I must be coping with this now, not ready till it will get worse? I imply, that appears apparent, however in some circumstances it’s not fairly as apparent.

Duncan: Yeah. Because it’s an annual, many of the annual weeds that folks will encounter must be eradicated, eliminated, after they first see them arising as seedlings or younger crops. And it’s no totally different proper now with the winter annuals. You see them arising and for those who acknowledge them as chickweed, for instance, then you need to actually eliminate them now, earlier than they go into the flowering section.

A number of the sorts of weed-control strategies that we all the time encourage right here at Mt. Cuba Middle is to go in and simply grub them out, utilizing bodily labor, and get them early on. They’re annuals; for those who pull them out of the bottom and expose the roots, they’ll dry up and die. So yeah, your intestine feeling is, “O.Okay., yeah, I see these little crops. It’s time to get on the market and begin weeding them out.” So you possibly can hoe them out or no matter you want to do.

Oriental bittersweet seedling in a sea of ground ivy or GlechomaMargaret: On the fringe of one other mattress, my nemesis is one among my many nemeses… And it’s not likely a horrible weed nevertheless it’s irritating as a result of it likes to crawl in from the sides of the garden, into beds, into decorative beds. And it’s Glechoma hederacea, what do they name it, creeping Charlie or one thing, floor ivy, is that what they name it? That’s one other one which proper now it’s prefer it has superior once more. It appears to have loved some current rains and who is aware of what this fall. [Above, ground ivy in the foreground with an Oriental bittersweet seedling and even one of garlic mustard in the middle.]

Duncan: Yeah. Glechoma hederacea is floor ivy. They’ll name it creeping Charlie. They’ll name it gill on the bottom or gill over the bottom as effectively. And it’s a perennial, yeah, it’s really a perennial weed that you need to actually attempt to eradicate each time you really see it, attempt to pull it out and take away it.

It has a reasonably dense root system. And it’s the type of plant that for those who can take away it bodily manually, the extra you possibly can take away it, the extra profitable you’ll be at stopping it from spreading, as a result of it does unfold over the bottom, therefore its frequent title, and it’ll persist. So yeah, it has taken just a little little bit of day without work. It’s gone just a little bit dormant within the dry a part of the season, and now it’s coming again. So I’d undoubtedly advocate you attempt to eliminate that as a perennial, and attempt to get the foundation system out. That’s the issue with perennials in fact, is that their root methods maintain onto quite a lot of saved meals and maintain these crops going.

Margaret: Yeah. And that is one the place it appears to the touch down in a number of locations, it’s like lengthy little runners and so they appear to have rooted in, in a number of locations, virtually vine-like above the bottom.

Duncan: Yeah.

Margaret: It’s nice when the soil is moist, it’s very satisfying for a loopy individual like me to type of pull it out gently, slowly, so that you simply get alongside the entire lengthy extent of it, so to talk. Yeah. In order that’s one other one I’m going to be tackling, despite the fact that once more, we’ve got snow forecast late this week, however so what, I’m going to do this; I’m going to do one other go on that one. And also you say that’s a perennial, in order that is sensible. After which there’s garlic mustard. [Laughter.]

Duncan: Oh God. Yeah. Garlic mustard [Alliaria petiolata, above]. Oh sure. Properly, the excellent news is you possibly can flip it into pesto in some unspecified time in the future, however you don’t wish to have that a lot garlic mustard in your property, do you?

Margaret: No. And isn’t {that a} biennial? We simply talked about a winter annual. We talked about a perennial. Is {that a} biennial? I believe, is it?

Duncan: Yeah, it’s. It’s a biennial. And what you’re in all probability seeing now’s what they name rosettes or small clumps of the plant that at the moment are arising. They’ve germinated and so they’re rising and so they’re in all probability three to four inches tall and so they’re only a collection of leaves. And so they have that attribute type of pungent odor to the foliage for those who crush it.

However yeah, you will get on the market and eliminate the plant proper now as a result of it’s going to go, once more, it’ll go to flower and seed very early within the season, come spring. So the extra you possibly can eliminate garlic mustard… It’s a biennial, so at this level once you pull it out, it’ll look like an annual as a result of the foundation system is simply from this yr. So pulling it out now might be well-advised as a result of A, you’re in all probability not going to get all of them. You’re going to 90% of them and also you could possibly catch the remaining few within the spring. However yeah, get them out now as a result of man, they’re up and flowering and seeding fairly early.

Margaret: And this one has quite a lot of weedy tactics. It’s profitable as a result of it’s a prolific self-sower, as a result of it’s allelopathic, I believe; I believe it exudes a chemical within the surrounding soil space that stops different crops from getting acclimated, getting began. It’s a tough one. So actually to get it out, as quickly as you see it’s important, I believe, earlier than it does these issues.

Duncan: Yeah. And never solely that, nevertheless it’s very tolerant of shade and solar. And so that you’re going to see it in every single place. You’ll assume, oh, effectively it’s shady over there, it gained’t invade. However no, it does. It takes the shade. The factor about it’s that, in fact it’s germinating and rising foliage this time of yr, after which within the spring, when there aren’t quite a lot of leaves on the timber above, they may proceed to develop after which rapidly go to flower. So, it’s a fairly sensible weed.

Margaret: It is extremely, nevertheless it’s not smartweed, which is the frequent title of one thing else altogether. [Laughter.]

Duncan: I do know. I do know. All proper. Sure. Smartweed. Though many weeds are sensible, there may be smartweed. Is that Polygonum, I believe? Anyway.

Margaret: Yeah.

Duncan: Yeah. I do know. And there’s many polygonums as effectively, so good god. [Laughter.]

Margaret: Sure. So we’ve simply talked just a little bit about figuring out not solely … figuring out its correct Latin title, ID’ing it, utilizing a few of the instruments, we’ll give some hyperlinks to, or having the precise ebook in your area, a discipline information for area. ID’ing it, attending to understand it by its correct title, doing just a little homework. Is it an annual? Is it a winter annual? Is it a biennial? Is it a perennial? That may get you a few of the technique brewing on methods to cope with it.

So let’s speak about management measures as soon as we all know that. So that you had been saying Margaret ought to get on the market and grub out these chickweed seedlings and he or she must be pulling, fastidiously pulling, a few of the perennials. And biennials like those we’ve simply talked about, the Glechoma and the garlic mustard. So what are a few of the different techniques of weed removing that you simply train?

Duncan: Yeah. Properly usually once we speak about we management, Mt. Cuba Middle tends to not depend on quite a lot of chemical measures. And so in school, we advocate that folks actually attempt to exclude weeds from moving into their yard to start with. And one of many ways in which they’ll do that’s that after they go to the backyard facilities or nurseries, they’ll take a look at the pots and containers that the crops are in, and if any of them have weeds in them, then they shouldn’t select these crops. And they need to be working with nurseries which are pretty diligent about preserving weeds out of their containers.

So we attempt to exclude weeds, however as , weeds… Dandelion seeds are blowing in, weeds are, simply coming in, generally from surrounding properties.

One other methodology that we advocate is to maintain your instruments as clear as doable. I do know it sounds mundane, however such as you, I’m on the market, I’m weeding, I’m utilizing my gardening instruments. After which I believe, “Oh, effectively I’ll simply put them down and choose up the place I left off tomorrow.” However the extra you retain them clear, the higher you’re going to have the ability to maintain weeds from coming into your … from spreading weeds round per se. Does that make sense?

Margaret: So from seed that’s on it or just a little bits of plant or seeds within the soil that’s left in it?

Duncan: It may be each. In case you’re digging up some mugwort [Artemisia vulgaris], for instance, and pulling it out and amassing mugwort [above], then the shovel you utilize could have little items of mugwort roots on it and also you’re simply transferring the spade to a different a part of your backyard. And also you’re going to make a brand new mattress, and immediately a yr or two later, you see mugwort cropping up within the new mattress. Once you assume, the place did that come from? So yeah, it may be seeds and it may be little items of crops as effectively.

Margaret: Proper. Which can also be true once you wish to transplant a fascinating plant from one mattress to a different mattress. If that mattress, the primary mattress, has some infestation of one thing you might be operating the chance of… for those who don’t wash off that division that you simply’re making of that. It may be a hosta, for goodness sake, which isn’t a weed, however for those who don’t wash it off, if there’s an adjoining weed in that mattress, it’s possible you’ll be bringing it alongside to the brand new mattress the place you set that division, yeah?

Duncan: Yeah. It’s so fascinating you talked about that, as a result of I’ve achieved precisely that the place I’m digging up a plant and I do know that plant X, the weed is in amongst these roots as a result of the weed tends to unfold round. And I’d actually, I’ll sit there and I’ll discern what’s the weed and what’s the root of the specified plant?

Margaret: [Laughter.]

Duncan: And I’ll tease all of it aside. Even when I lose all of the soil across the plant I’m transplanting—a herbaceous perennial, for instance—I’ll attempt to be as meticulous as doable at getting all of that little weed root out of there. And so it form of means it’s important to know what the weed root seems like and the foundation of the fascinating plant. So it’s not simply the leaves and the flowers of the weed, it’s important to know one thing about their roots. However yeah, it’s important to be very diligent. Good level.

Margaret: Yeah. So these are some preventive issues. Grubbing out is one removing space. What about can I exhaust a few of these crops, like with repeated a few of the ones which are extra tenacious? If I can’t get them out utterly, what are another techniques?

Duncan: Yeah. I imply stopping our weeds from going to seed as we talked about earlier, getting the little seedlings out proper off the bat. However with perennial weeds, and you may consider issues like plantain [below] or dandelions or what else can I consider?

Margaret: Thistles. These rattling thistles. All these thistles.

Duncan: Thistles, yeah, I do know. And thistles have roots from right here to eternity, however we’ll attempt to put that on maintain for the second. With issues like perennial weeds of that nature, then you definitely actually simply must get at getting the foliage out as typically as doable. Take away the foliage as typically as doable. Mow it down, pull off the leaves, attempt to dig it out and take away it.

The extra you possibly can take away the foliage, the weaker the plant will change into, which means that the leaves are the supply or the positioning of photosynthesis. And that’s the supply of the plant’s meals. And with out plant meals, then the roots aren’t going to proceed to develop.

So for those who take away the leaves, take away the supply of meals for the plant itself, then you’ll finally weaken it. And it’s important to be very diligent about this, as a result of these leaves are going to return popping again, as you effectively know. However for those who actually do maintain at it inside three or so years, you possibly can in all probability actually, actually maintain that weed down.

Margaret: Proper. So no photosynthesis is finally no plant, proper?

Duncan: Yeah. Precisely.

Margaret: So stopping photosynthesis. Yeah.

Duncan: Proper, proper, proper. And talking of that as effectively, we do speak about mulching and mulching is-

Margaret: I used to be going to say, do you mulch?

Duncan: We do mulch right here with leaf mulch. And in one among our gardens, we’re mixing up a few of our do-it-yourself woody plant-sourced mulch with the leaf mulch. So it’s type of a half-and-half. It’s a really finely shredded woody materials, and the leaves which were shredded as effectively. So it’s not like a rough mulch such as you would see on the backyard facilities on the market.

So type of is a transition space form of between a compost, type of factor.

However yeah, we do mulch, and I believe the essential factor about mulching your backyard is to make use of one thing that’s natural clearly, and to layer it as much as 2 to three inches. I bear in mind years in the past there was analysis achieved on what’s the depth of mulch that you need to use. And customarily they got here up with three inches of depth as a result of that may forestall weed seeds from germinating, and so forth. Some individuals say 2 inches. I’m extra inclined to say three inches as a result of then, you possibly can go away it there alone. Because it decomposes, it’s important to clearly, renew it. So if I layer on round three inches of mulch round my backyard crops, then I don’t must continually reapply mulch. You recognize what I imply?

Margaret: Proper, proper. I simply wish to rapidly simply shout out that I get just a little nervous, and I shared this with you on the telephone the opposite day, I see the large bottles of acetic acid, so-called horticultural vinegar, within the shops—within the backyard facilities—and I shudder considering of everyone spraying them with out the precise correct safety. Do you ever use these, the acetic acid, the horticultural vinegar in any respect? And what’s it for, if it’ll be used?

Duncan: We aren’t utilizing the horticultural vinegar, no.

We’ve got had some extent of success utilizing another merchandise right here on the backyard. Natural chemical substances principally work in the identical sense as you’d apply to eradicating the highest foliage. So in a perennial state of affairs, you wish to take away the leaves. Even with an annual, for those who take away the leaves, you’re going to essentially take away the plant.

So a few of the merchandise that we’re utilizing listed here are principally made out of pelargonic acid combined with fatty acids, or citric acid and clove oil. One other product that we’ve used is one which has lively chelated iron. And so they principally act as foliage burns. They burn the foliage. And in that sense, they’re in all probability handiest on younger crops. So we’ve got used some right here on the grounds. I can distinctly odor the clove oil every so often. However these merchandise aren’t selective.

And once you stated you cringed earlier with horticultural vinegar, even with these merchandise, you’ve acquired to be very, very particular in concentrating on the plant you need, as a result of something inexperienced that they’re sprayed on will probably be broken.

So I believe that the very best strategy could also be to attempt to do handbook removing. Attempt to plant your backyard beds as densely as doable with the crops you need. I imply, weeds are very sensible.

Margaret: Proper; to outcompete weeds, proper.

Duncan: They get into areas which are open and out there. So we do advocate that you simply make your backyard beds pretty dense with the crops that you really want. We use native crops clearly. And we attempt to not use the natural compounds, however as I stated, they’re very efficient on younger crops, however they’re not selective.

Margaret: Proper. And all the time learn the label and use the safety—eye gear, and so forth., that it says to make use of on the label.

Duncan: Completely. Sure, completely. And don’t assume twice as a lot is best as a result of the-

Margaret: No, no, no, no, no, no, no.

Duncan: As a result of the businesses which have developed these know that that is the focus you wish to use.

Margaret: Properly, Duncan, I hope you’ll come again and speak about one among your different courses, the native groundcovers, as a result of I do know that may be an enormous hit. And like I stated, I’ll give hyperlinks to all of the weed resources [more links below] and the classes that you’re offering on demand now from Mt. Cuba. And I thanks a lot for making time in the present day.

Duncan: Yeah. Properly thanks, Margaret. It’s been a pleasure speaking weeds with you and yeah, groundcovers is one other massive favourite of mine.

Margaret: Good.

Duncan: And so I look ahead to listening to from you once more, and want everyone the very best of their winter weed management.

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MY WEEKLY public-radio present, rated a “top-5 backyard podcast” by “The Guardian” newspaper within the UK, started its 11th yr in March 2020. In 2016, the present gained three silver medals for excellence from the Backyard Writers Affiliation. It’s produced at Robin Hood Radio, the smallest NPR station within the nation. Hear domestically within the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Jap, rerun at 8:30 Saturdays. Or play the November 2, 2020 present utilizing the participant close to the highest of this transcript. You may subscribe to all future editions on iTunes/Apple Podcasts or Spotify or Stitcher (and browse my archive of podcasts here).