Sunday, 19 April 2015

Lesser Celandine: how to remove it

I had a question today, (*waves to Seb*) asking for suggestions as to how to remove an infestation of Lesser Celandine.

First the basic Botany: Lesser Celandine (Ranunculus ficaria) is part of the Buttercup family, and is not related to Greater Celandine (Chelidonium majus) which is part of the Poppy family. This is why you have to learn the "proper" names of plants and wildflowers; common names are often seriously misleading!

If you are lucky enough not to know about this little beastie, this is what it looks like:

It is a small, low-growing, ground-hugging plant with rosettes of long-stalked rounded leaves, and single bright yellow flowers on stems a couple of inches high.

The leaves are glossy, sometimes heart-shaped, sometimes kidney-shaped, but always indented where the stalk joins the leaf - "cordate" is the technical term.

They flower now, April, then the whole thing dies back and disappears for another year, so they can only be dealt with while they are visible.

They spread quickly, forming a dense mat of foliage which tends to smother all other plants, choking out all the dainty spring wildflowers - it is often described as an "aggressive and unwanted garden invader" but in a woodland setting, it can create a carpet of shiny yellow.

It spreads in no less than four ways - each individual rosette grows in size and spreads by rooting, creeping stems: by seed, by small white bulbils in the leaf axils above ground and (worst of all) by tubercles, which are tiny tubers, each of which can grow into a new plant. These form at the base of the plant, so when you try to dig it up, they easily get dislodged and fall, unseen, back into the soil.


They are also the reason for the scientific name - "ficaria" means "fig-like" and they do look a bit like tiny figs.

Here is a photo of the base of a plant, showing the collection of tubercles or tubers.

So, how do we get rid of this little blighter?

As usual, catching it before it gets too bad is the real answer, but - as usual - that is easier said than done, and if you move into a garden with a heavy infestation, then hard work will be required.

The bad news is that smothering them - with black plastic, or with deep mulch - does not work, so digging them out is the only answer.

If you have a "spotty" coverage of them, then take a trowel and chop vertically downwards around the plant just inside the range of the leaves.

Hang on, a picture is worth a thousand words: *quick search of google images and application of Paint*

There: to remove a single clump, lift up the leaves and cut vertically downwards with a trowel, roughly where the circle lies. Go down about 3-4", then lever out a plug of soil with the roots in it.

This is specifically to avoid the risk of dislodging any of those pesky tubers.

Place each plug carefully in the bucket or wheelbarrow, then put the whole lot into your "green waste" bin to be disposed of by the council, whose heat treatment plants should kill it all. When you have done them all, either fill the plug holes with home-made compost, or fluff up the soil around the hole with a small fork, so that it fills in the gap.

Whatever you do, don't even think about dumping this garden waste over the back fence, or on a road verge somewhere, as that will just spread the infestation.

If you don't have a green waste bin, then put the material into bags and take it to your local dump: again, the waste there will be heat treated.

If you have large areas to deal with, there are three ways to approach it.

1) Get on your hands and knees and dig out plugs day and night for the next month. This is quite hard work, boring, and will leave you with lots of little pits. But it will get rid of them.

2) Dig up the top 3" of the entire area. This will be very hard work, may even require a small digger, and what do you do with the spoil? You will probably have to pay for a skip and proper disposal, otherwise wherever you tip it out, a colony of Celandine will appear.

3) Weedkiller.... yes, I know, howls of protest from Christine the glyphosate-hater, and everyone else who abhors the use of chemicals, but there are times and situations where it is the only sensible option. Bearing in mind how invasive this plant it, and the risk that anyone you pay to cart away a couple of tons of soil/tubers may well just illegally dump it in the nearest layby, well, it might actually be more responsible of you to use a weedkiller.  If you do, read the instructions carefully, apply it exactly as per instructions regarding dilution, time of application, etc, use the minimum, don't do it on a windy day, and take photos before and after, so that you know which areas have been sprayed.

4) Unsubstantiated internet research: "a dressing of coal or wood ash is said to reduce an infestation of Lesser Celandine" according to this website but I have not tried this for myself, so I can't comment on its effectiveness.

With regard to timing, it would be better to dig the plants up in very early spring, as soon as you see the first leaves, and before the bulbils have formed, thus reducing the risk of spreading viable material around. Likewise for the use of glyphosate, better to catch them in early spring when the leaves are fresh and before they flower, thus hopefully killing them before they set seed.

And a final word, be careful to clean all soil off your tools (and boots) before using them elsewhere, to avoid spreading the plant around.

Like all these garden invaders, it can be dealt with, but it takes hard work, and patience: but the more of them you can get up this year, the fewer there will be for next year.

UPDATE:  After receiving a question, I have written another article dealing with the topic of how to remove this pesky weed when it has infested a lawn.

USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CHECK THE INTERNET AND/OR YOUR LOCAL COUNCIL FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. 
 
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL. 

 

Did you enjoy this article? Did you find it useful? Would you like me to answer your own, personal, gardening question? Become a Patron - just click here - and support me! Or use the Donate button for a one-off donation. If just 10% of my visitors gave me a pound a month, I'd be able to spend a lot more time answering all the questions!!

11 comments:

  1. Wow! Thank u for the information. I woke up one day recently and these were all over my flower beds. This really did help me to decide what to do. I have a long summer ahead of me lol.

    ReplyDelete
    Replies
    1. You're most welcome - I'm just sorry to be the bearer of bad news!

      Delete
  2. Good info Rachel. Perhaps useful to note that our council and native plant community specifically says not to put it in the green bin as the risk of spreading it with their compost byproduct is too great given how robust the tubers are. Bag it and bin it is their advice.
    It’s a nasty plant that will totally colonize your yard in a few short years. Deal with it early and don’t let it flower.

    ReplyDelete
    Replies
    1. Interesting to hear that your local council specifically advise against it: I've been to the Oxfordshire recycling plants (all three types - garden waste, food waste, landfill waste, use the Search box top left of the page to find the series of articles) and the green waste process is more than enough to kill all celandine tubers. Here, we are not allowed to put garden waste into our landfill bins, so their advice to bin it made me laugh!

      Delete
  3. I’ve also experimented with torching but it takes multiple applications and doesn’t completely eliminate it.

    ReplyDelete
    Replies
    1. My first reaction is to laugh like a maniac and scream "Burn, baby, Burn!!" but seriously, I have found those flame wands to be quite ineffective for many weeds, let alone one as persistent as this one!

      Delete
  4. We've just moved into a house and had a full infestation along the back flower bed, which we've dug out. But it's also invading the law - a band perhaps 1.5 meters deep at the back of the garden is now a 50/50 mix of grass and lesser celadine (morer celladine, we call it). What do you think we should do with the lawn? I don't want to dig it up and re-lay turf as that may be a different colour to the existing lawn, which is quite big. Is there a weedkiller that will terminate the morer celladine but not the lawn?

    ReplyDelete
    Replies
    1. "More-er Celandine" *hoots with laughter*

      I hardly dare tell you that there is actually a thing known as Greater Celandine... mind you, it's big, but it's nowhere near as much of a pest as this little thing!

      Check item 3) above: as a last resort, yes, try weedkiller, but there are some implications, if it's already 50% into the lawn, in that area. It's such a good question that I've written a new article to answer the question properly, so check back in tomorrow - once it's published, I'll come back and put a link in this article.

      Delete
    2. Here's the link to the new article:
      https://rachel-the-gardener.blogspot.com/2021/04/lesser-celandine-fight-continues.html

      Delete
  5. Thanks for the advice! I spent a good part of two days trying to cover the patches of celandine with newspaper, then compost (mostly grass cuttings), on advice from a friend. I'm afraid to use herbicides because I have native flowers and raspberry canes in the garden, now invaded by the celandine. What effect would glyphosate have on them?

    ReplyDelete
    Replies
    1. Hi Jean,

      The problem with the "smother-em" method is that it will also kill everything else under the paper: grass, wildflowers, everything: so you'll end up with a patchwork of strangely regular bare areas! And in my experience, as mentioned in this article, smothering them does not actually solve the problem: the seeds, and those fig-like tubercles, live on in the soil, and spring to life when you eventually remove the cover.

      Glyphosate will kill the Celandine: it will only kill your wildflowers and your raspberries if you allow the spray to drift onto them. So the answer is to follow the advice in section 3) above, and to spray very carefully.

      Good luck!

      Delete

Comments take 2 days to appear: please be patient. Please note that I do not allow any comments containing links: this is not me being controlling, or suppression of free speech: it is purely to prevent SPAM - I get a continual stream of fake comments with links to horrible things. Trust me, you don't want to read them....