What is Lesser Celandine?
Lesser celandine is a short life-cycled perennial in the buttercup family, native to Europe, North Africa, and parts of the Middle East. Today, it has become widely established in eastern North America and the Pacific Northwest, as well as Japan and New Zealand. It has a low, dense, spreading growth habit and a very early growing season. Lesser celandine can be rather easy to identify, as the small, bright yellow flowers are among the first to appear on the landscape- in Lincoln County, blooming usually begins around mid-March and lasts until early to mid-April. Flowers are simple in shape, glossy, with 7 to 12 petals. The leaves are heart-shaped and glossy, dark green on the top surface and paler green underneath, and first emerge in late winter. By the end of May, foliage dies back and the plant enters a six-month dormancy phase. Lesser celandine can spread by seeds, but primarily spreads vegetatively through root tubers and above-ground stolons. It prefers growing in seasonally wet- but not waterlogged- locations.
Why is Lesser Celandine a Problem?
The early growth period of lesser celandine enables it to pre-emptively outgrow neighboring native species, spreading its root systems and crowding out other nearby plants before they have even come out of dormancy. This especially hinders the growth of ephemeral spring-flowering native wildflowers such as trillium and fawn lily, which can easily lose their short, single-season growth period to lesser celandine encroachment.
Lesser celandine’s ability to propagate from broken-off root tubers makes infestations very easy to spread via soil disturbance. Digging or tilling soil with lesser celandine tubers present will create many more individual plants, and tools or machinery with tuber-containing soil stuck to them can accidentally transport the plant to new locations. Erosion and flood events may also spread lesser celandine without human or animal interference; as such, low-lying, flood-prone areas are often more susceptible to lesser celandine infestation.
Controlling Lesser Celandine
If caught early, lesser celandine may be eradicated by hand-digging the entire plant, then bagging and disposing of it in landfill garbage. Do not attempt to shake dirt loose from removed plants- even a single small tuber can begin a new infestation if dislodged. If the infestation is larger than a few singular plants, manual control will likely not be possible and attempts at such can worsen the infestation. Solarization or mulching have not shown to be effective due to the plant’s ability to undergo long dormancy periods- infestations usually return as soon as open surfaces can be found.
Larger infestations of lesser celandine can be controlled and- if treated consistently- eradicated by foliar applications of herbicides such as glyphosate and imazapyr. Any herbicides used should only be applied in accordance with label directions.
While chemical control of lesser celandine is the most effective eradication method, application can still be tricky due to the timing of the plant’s life cycle. As foliage first emerges during winter and dies back by the end of spring, finding a window of time in which weather is suitable for foliar herbicide applications can be difficult in the Pacific Northwest’s rainy climate. The short growth window also makes it difficult to plan for effective treatment within the same year as an infestation is first noticed. As lesser celandine is a new introduction to Lincoln County, and distribution within the county is currently limited, this species is a high priority for Early Detection Rapid Response treatment. Lincoln SWCD’s licensed herbicide applicators are available to assist in treatment of this invasive plant.
If you believe you have discovered an infestation of lesser celandine, report it to Lincoln SWCD by emailing LSWCD or by phone at (541) 265-2631.