TheMondayGarden.com

PICTURE: lesser celandine along 3rd Street, Stamford CT, Spring 2004

How lesser celandine grows and spreads: Lesser celandine's leaves emerge in the form of a basal rosette (circle of leaves close to the plant's base) in late winter; the flowers follow in early spring (late March- early May in Zone 6 -- just before the forsythia blooms). Marsh marigolds, and most other self-respecting native forest/stream wildflowers, emerge a bit later which gives lesser celandine the edge in competing for resources.

As the lesser celandine's flowers bloom, tiny bullets form along the stem. By June, the flowers are gone and the plants are dying back into the ground to escape summer heat and drought. The bulblets remain on the soil's surface. Some of the bulblets root in place, adding the lesser celandine colony's already dense carpet that chokes out all other plant life.

Many of the bulblets get carried away by run off into the sewers and flooding into the water ways to start new colonies. Each June, along the banks of Stamford's Mill River, north of town, thousands of these little bulblets lie along the bank, just waiting for the next high water to spread them further down stream.

Lesser celandine, however, is also commonly spread by human gardeners. Some innocently dig up some of the pretty plants from along the road or a neighbor's yard and take them home to ruin their lawns. Some gardeners actually buy the stuff! (Believe it or not, lesser celandine cultivars are still widely sold. Please don't buy them, and please tell the nursery that you wish that they would stop stocking invasive plants and invasive plant wannbe's, whether or not the plant is controlled by the law of your state). Gardening equipment is also to blame for spreading lesser celandine. For example, a patch appeared in my mother's lawn last spring in a place where the only source of contamination could have been the lawn mower's equipment.

picture: lesser celandine annoying the skunk cabbage, along the Mill River at Scalzi Park, Stamford CT. Spring 2004

Getting rid of lesser celandine : Unfortunately, by the time you have a major carpet of lesser celandine, you almost can't get rid of it. The key is to be vigilant should a small patch appear in your yard. It is also important to realize that if you harbor this alien in your yard, that it can escape via mowing equipment and water run off to do damage to our remaining wild places.

Mechanical: Small clumps can be removed by hand and persistent removal can be successful but you're talking about years of dedicated stoop-labor for a bad patch. Note, that you have to get every last bit. If you leave any of the tubers or bulblets, they'll flourish in the ground that you disturbed when digging the main plant. Unless you come back, year after year, to dig out the progeny, the end result will be more plants than before the soil was disturbed (plus every other weed that was in the seed bank).

Sterilization: Even more sadly, any of the more drastic eradication measures, such as sterilizing the ground with a black plastic cover, will kill all the plants that you were trying to protect from the lesser celandine. Soil sterilization is described in: INVASIVE PLANTS: KILLING AND CONTROLLING (THEM, NOT US), April 2005 Issue 160>. Sterilization is a last resort since it will not only wipe out the plants that you're trying to save, but also the beneficial soil critters.

Chemicals: It is reported that some forest custodians have resorted to a broad-leaf weed killer before other spring plants emerge. This, though, raises all the questions about use of pesticides; and there are many of us who believe that the cure is invariably worse for the planet then the original problem. If the weed killer knocks out the bad plant but gives the frogs cancer, was it worth it?

Biological: There is no known biological control (e.g. plant eating bugs, goats, what have you) that won't also wipe out the good guys.

Best Known Solution: Accordingly, the only known good way to handle the problem, short of sterilizing a major chunk of land, is to hand remove lesser celandine.

--Use a small towel and shovel to get under the underground tuber and get the whole plant, but be gentle so that you disturb the ground as little as possible.

--Remember to work inwards from the edge of the patch, slowly pushing the patch inward.

--Remember lesser celandine is only visible above ground late winter to early summer, so you need to time your attacks on it accordingly. You want to root out the plant before the little bulblets form as they can drop off the plant, back into the soil and start your problem all over again.

Something new to try: Lesser celandine is a shade plant but how much shade can it take? Try staking a tarp a couple inches off the ground so you don't smoother the good soil critters or kill the seed bank. I wonder if, after a year or two, this will get the number of plants down to something manageable. The tarp should be in place as soon as the ground thaws enough in the spring to drive the stakes and kept in place until June. Removal of the trap for June- December will let the soil recover and give the later season plants a chance. If you try this, please post a comment. (keep the tarp off the ground by driving stakes every few inches.)

PICTURE: lesser celandine along the Mill River, north of Bridge Street, Stamford CT, Spring 2006. ALL (yes, ALL) of the green in the low right is lesser celandine.

PICTURE: Detail of the prior picture: a mat of lesser leaves celandine along the Mill River, north of Bridge Street, Stamford CT, Spring 2006

Identifying lesser celandine and marsh marigold: Both lesser celandine and marsh marigold are low-growing with shiny green, rounded leaves, and big, shiny buttercup-like flowers.

There are major differences in the appearance but the quickest way to tell the two apart is by behavior. If you come across an entire yard, stream-side or forest choked with the stuff, it is lesser celandine. Marsh marigolds grow in mannerly clumps; they don't take over.

In case you come across a small clump of buttercup yellow-flowered something and are trying to determine whether it is one of the good guys, here are some of the more subtle differences between lesser celandine and marsh marigold:

--Lesser celandine generally has 8 petals (can be to up to 12) or is double-flowered; marsh marigold has 5 to 9 petals (actually sepals, if you're a botanist).
--Lesser celandine has kidney to heart shaped leaves; marsh marigold leaves are rounded to kidney shaped.
--Lesser celandine make bulblets along the stem and has an underground tuber; marsh marigold does not.
--Lesser celandine tends to grow a foot or less in height-- around where I live it's ground hugging; marsh marigold can get to be 2 feet tall.
--Lesser celandine has been hybridized to include varieties with variegated leaves and double flowers

What can you do? Save some of the endangered wildflowers by planting them in your garden instead of the invasive ones or the "just pretty" ones. Of course, never ever collect endangered plants from the wild and buy only from reputable dealers who grow their own stock from, hopefully organic seed.

What is greater celandine?. The real celandine (Chelidonium majus) is a biannual herb in the poppy family from Europe and Asian, historically used for medical purposes (but not generally proven to be effective and has raised questions about possible extreme side effects like liver damage). Celandine's naturalized in woodland areas in northern U.S. and southern Canada. It does co-exist with others, so it is not considered a particular threat to native flora (at least at this time).