A plant too invasive even for me

Ann Burlingham asked on Facebook for an identification of a plant in her Pittsburgh garden, which turned out to be Houttuynia cordata, chameleon plant:

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A stunningly invasive plant, which spreads by what I’ve called dragon-toothing: any tiny bit of the plant will root and turn into a new plant. In Columbus OH, I engaged in what I thought of as “gardening with invasive plants”, but there were a few plants that were too invasive even for me, and this was one.

On the plant, from Wikipedia:

Houttuynia cordata, also known as fish mint, fish leaf, rainbow plant, chameleon plant, heart leaf, fish wort, Chinese lizard tail, or bishop’s weed, is one of two species in the genus Houttuynia … [in the Saururaceae, or lizard’s-tail family]. It is a flowering plant native to Japan, Korea, southern China, and Southeast Asia. It grows in moist, shady locations.

Houttuynia cordata grows in moist to wet soil or slightly submerged in water, as long as it is exposed partially or fully to the sun. It can become invasive in gardens and difficult to eradicate. It propagates by division.

… It is commonly grown as a leaf vegetable, and is used as a fresh herbal garnish. The leaf has an unusual taste that is often described as ‘fishy’ (earning it the nickname “fish mint”), so it is not enjoyed as universally as basil, mint, or other more commonly used herbs. [Used in Chinese, Vietnamese, and northeastern Indian cooking, as a green or garnish or cooked with other vegetables or fish, and its roots can be ground into a spice.]

[Brief digression on the plant family. From Wikipedia:

Saururaceae is a plant family [not previously written up on this blog, now #81 on my list] comprising four genera and seven species of herbaceous flowering plants native to eastern and southern Asia and North America. The family has been recognised by most taxonomists, and is sometimes known as the “lizard’s-tail family”.

The species: Anemopsis californica, Gymnotheca chinensis, Gymnotheca involucrata, Houttuynia cordata, Houttuynia emeiensis, Saururus cernuus (lizard’s tail, water-dragon), Saururus chinensis

The type genus name Saururus comes from Greek sauros ‘lizard’ (cf. the -saur of dinosaur, Tyrannosaurus, etc.; and the name Sauron, of the title character and chief antagonist of Tolkien’s Lord of the Rings), plus oura ‘tail’ (cf. ouroboros ‘tail-eater’, a symbol depicting a serpent or dragon eating its own tail).]

I was convinced I’d already posted about Houttuynia, but couldn’t find anything on this blog or LLog. Well, it seems I did, but on the Usenet newsgroup rec.gardens, on 1/2/98. Lightly edited:

Judith Reed asks for advice:

It’d be interesting to hear of other’s experiences with the plants we are yearning for, too, if you want to comment… Some of my yearnings: [a list of assorted trees, bushes, and seriously tall flowers, ending with Houttuynia, chameleon plant]

Over the years, many people have posted here about Houttuynia. The usual advice is to plant it only if you can put it in a place where it can be contained by an impregnable barrier running many feet underground. It sends down very deep roots and spreads like crazy. Also, if you break a stem or leaf, it gives off a scent that many people describe as a stink (though it’s used in small quantities in Southeast Asian salads; no one could, however, imaginably eat up a stand of Houttuynia).

I myself spent years ridding my Ohio garden of this pretty pest. If you live any place where there’s real frost, it probably won’t survive in pots; any part of the plant that freezes dies. (It survives in gardens thanks to those deep deep roots.)

Arnold, shuddering over the Three Evil Invasives in his Ohio garden: Houttuynia, Campsis radicans [trumpet vine], and some wicked polygonum [Fallopia japonica, Japanese knotweed]

From my 3/26/16 posting “Monsters of vegetative spread: dragon’s teeth”:

Vegetative spread proceeds by division, by creeping (above or below ground), by vining, or by a method I’ll call dragon-toothing.

… Each fragment [of the plant] is a dragon’s tooth, from which a fresh threat can come forth, as in Greek mythology.

(with a reference to Japanese knotweed, as treated in a 7/9/14 posting).

And then on my approach to gardening in Ohio, from the 8/22/15 posting “Seedy invasives”:

Some time ago, I contemplated writing a book on Gardening with Invasive Plants, describing my own experiences (including some less than happy ones as well as the triumphs). I started with a 1991 posting to the newsgroup soc.motss, which I edited lightly for a 2010 posting“Our Gardens, Our Selves” on AZBlogX (though there’s virtually no sex in it).

Houttuynia  spreads by both creeping and dragon-toothing, so it gets an especially severe warning from Marie Ianotti in her 2/25/17 piece on the Spruce site, “5 Ground Cover Thugs to Avoid”:

It’s hard for a new gardener, and many experienced gardeners who should know better, to resist this plant. Although the flowers are hardly noticeable, its leaves are an eye-catching mix of red, cream, and green. While I’ve known many gardeners who have succumbed to its charms, I don’t know of any who would recommend it to others. Most are still trying to get it out of their gardens, decades after planting it.

Chameleon plant is a very rapid spreader. Its fleshy rhizomes reach out and over anything in its path, forming a thick mat of roots that are impossible to thoroughly fish out and remove. Any remaining root will simply form a new plant and continue spreading. If you can smother it, as I describe [in a section on] bugleweed, or use one of the techniques discussed in this article, you should have success killing it eventually. But that’s not always possible, when it’s become intermingled with other plants. Sometimes you have to sacrifice a few innocent plants, to finally rid the area of this thug.

I went through several iterations of digging out the roots and then smothering the bed where I had planted the Houttuynia (which a local nursery had recommended as a pretty, easy-to-grow ground cover), and I eventually prevailed, but it was a tough battle.

Ianotti’s full list of ground covers to avoid:

bishop’s weed (Aegopodium podagraria), bugleweed (Ajuga species), chameleon plant (Houttuynia cordata), evening primrose (Oenothera speciosa, Mexican (evening) primrose), English ivy (Hedera hibernica and Hedera helix Baltica)

Bishop’s weed and bugleweeed we encouraged in the Columbus garden, just ripping them out when they spread to places we didn’t want them in. Same with ivy, here in Palo Alto as well as in Columbus. Never tried Mexican evening primroses (they’re seedy invasives) in Columbus, but they’re all over the place here in Palo Alto, where they’re planted in traffic circles and the strips along the streets. This is their high season, and they’re gorgeous. From a year ago, in my 5/28/17 posting “In the neighborhood, with an O”:

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8 Responses to “A plant too invasive even for me”

  1. arnold zwicky Says:

    On Facebook, Chuk Craig notes the use of flame weeding by organic farers, reported on here:

    https://boingboing.net/2018/05/25/watch-how-organic-farmers-use.html

    I did contemplate taking an acetylene torch to the Houttuynia. Instead, I tried boiling water, but I guess I didn’t boil enough of it.

  2. annburlingham Says:

    Boy howdy, have I got something I can use as a “gift” for any nemeses now.

  3. Catherine Kohn Says:

    Hi Arnold, I read with great interest your comments about the ghastly invasive plant that never dies, Houttuynia. It has taken over a portion of my garden on Zeller Rd, very near your Columbus house. I have tried to dig this plant out, but I never get all the roots and back it comes with great vigor.

    I hope this message finds you well; I am sorry to have lost track of you.

    All best from Columbus!

    Catherine Kohn

    • arnold zwicky Says:

      Catherine! How wonderful to hear from you! (I am suddenly *inundated* by messages from people I haven’t heard from in years, back to, like, 60 years ago.) (For other readers, this is Catherine Kohn VMD, emeritus faculty in the veterinary clinical sciences department at Ohio State in Columbus. She and I were companions in Sacred Harp shapenote singing in the late 1980s / early 1990s.)

      I am terribly sorry to hear that you are afflicted with Houttuynia.I started by killing the visible stuff with boiling water (supremely safe ecologically), then covering the whole affected area with thick dark paper held down at the edges with heavy stones, so that it would cook in the sun for a season. Remove the paper, kill the new growth with boiling water, and put on a new layer of paper. Repeat. In three years or so, you will have killed the stuff. DO NOT DIG IT UP; every tiny piece of it will start a new plant. It is truly Satanic.

      Meanwhile, I miss your company. I haven’t been able to travel anywhere for 15 years, so I’m not likely to get to Columbus. Please send me some e-mail about what’s been happening in your life.

  4. Elizabeth Says:

    How to eradicate houttuynia cordata (chameleon plant)

    What I did when Houttuynia cordata took over my garden beds. I was one of those unsuspecting persons who thought this was a lovely groundcover and brought a couple home. For a couple of years due to my job, I did not have much time as I would have liked to tend my garden. I did not know what this plant was going to do. When it was in bloom, the little white flowers seemed to add a sparkle to my landscaping. And then it happened. The penalty I paid for admiring this plant and letting it spread was that my beds ended up completely smothered and taken over by this plant. In my yard, the chameleon plant behaved like fairy sized kudzu. In July 2019 I began researching online and was thrown into a panic. The prospects did not look good for getting rid of it. I found out this plant is on the list of globally invasive problem plants. I was stressed. I am going to tell you what I did after reading everything I could uncover on the internet about trying to get rid of this plant.
    I have never knowingly put any chemicals in my yard. I do not like them and I do not want to harm any wildlife or the ecosystem. However, in this instance, seeing how aggressive this plant was and having read that it can even spread under a driveway, I made a personal decision to use Ortho Poison Ivy Spray. It was not a decision made lightly. I did not want this plant taking over anymore of my property, spreading to my neighbors’ yards, or escaping into the wild areas where I live.
    From July to early September, I carefully applied the spray. The container it comes in has a very narrow stream, so I was able to be careful and not lose any plants I didn’t want to. After this application during the hottest months in Memphis, TN, the offending plant began to look dead. But from my research I knew it is a zombie that would return come Spring. My next step was sheet mulching. My beds needed to be re-done anyway, so in my case, I just dug up plants that I absolutely needed to save and moved them and with a few – like my Baptisia that have long taproots and can’t be transplanted, I worked around.
    1. In September my partner and I got a lot of cardboard. My source was behind stores like TJ Maxx. After they unpack clothing etc….they put all of the cardboard behind the retail establishments. The cardboard was clean. I removed any tape. I had purchased a large supply of landscape pins. I used the sheet mulching method. Heavy layer of cardboard, then wet it and had humus and triple milled hardwood mulch delivered and applied on top of the cardboard. The beds stayed like this until March when I began putting in new plants and shrubs.
    2. Spring 2020. A silver lining to Covid Times, I worked from home through the Spring. This enabled me (with the help of my partner) to re-do my front garden beds and tend them everyday. After planting all of my new plants and shrubs and mulching with pine straw I checked every morning for any reappearing houttuynia leaves. Whenever one sprouts up, I zap it with poison Ivy spray. Yes, there have been a few that have popped up. I still do not like using poison. I am still getting rid of the plant, but honestly, so far the reemergence has been very easy to handle. Mostly because I have checked it everyday. I know I will have to keep on this, but I feel like I have it under control. I just hope I can continue to be vigilant next Spring when I will be at work. Meanwhile, my new landscaping is settling in. I planted a lot of natives, and my garden is humming with pollinators. Don’t give up.

  5. Laurie Says:

    Elizabeth, curious how your garden beds look now? We have this invasive plant taking over our entire backyard landscaping. We think we got it from a local nurseries mulch. We have been battling it for three years now. We have an in ground pool so we always avoid pesticides and harmful chemicals. This spring we are planning on heavy black tarps to kill it off. We plan on keeping these down for the next two years according to other posts. We are sacrificing all plants unfortunately.

  6. Marilyn Quinn Says:

    I just bought the tarp to put down. A couple workers carefully dug it up and screened the soil. Most of the soil was removed by them in bags. I spend hours sifting and digging and put what I find, even if it is suspicious, in a special container. I have been doing this for a year. I have not noticed new plants yet, but my roughly 6 by 7 foot garden is gone. I removed all hostas, iris, rosemary bush, etc. etc. last summer. I may be digging up and removing some others nearby to be on the safe side. It is still growing under the patio and between the house and the patio. A landscaper will remove the patio this spring and will probably do some gyphosate spraying. I hate the stuff, nevery used it. By I have found that pouring a strong solution of white vinegar on a couple leaves caused the leaves to die in less than a day. Will continue with vinegar and carefully sifting. I am considering removing more soil very carefully. I am 76 and I did not plan on a plant I bought a few years ago to destroy my garden like this.

    • arnold zwicky Says:

      I am so sorry to hear of your travails. Apparently, repeated acetylene torching will do the trick. But of course that can’t be done close to the house or other structures. (Killing the leaves will not do; you need something systemic, to destroy the root system. I remind readers: DO NOT DIG IT UP. Every tiny bit of root not removed will establish itself as a new plant. Dragon’s teeth.)

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