You Have 8 Weeks to Kill It
Lesser celandine appears in February and vanishes by May. Miss that window and you’re waiting another year while underground tubers multiply. This pretty spring flower is one of the hardest weeds to eradicate.
Lesser celandine (Ficaria verna) is a spring ephemeral that spends most of the year hidden underground as tubers. For a brief period in late winter and early spring, it emerges to carpet shaded ground with glossy yellow flowers before disappearing completely by early summer. This hide-and-seek lifecycle makes it one of the most challenging weeds in UK gardens to control.
The plant is native to the UK and was once valued for its cheerful early flowers. But lesser celandine has a dark side. It spreads aggressively through underground tubers and stem bulbils, forming dense mats that crowd out other plants. In woodland gardens and shaded borders, it can become a serious problem.
Why Lesser Celandine is So Difficult
Lesser celandine has three methods of spreading, making it exceptionally hard to eradicate. The primary method is through underground tubers, small potato-like structures that store energy and survive dormant in the soil for years. Each tuber can produce a new plant, and a single established clump may have dozens of tubers beneath the surface.
Some subspecies also produce bulbils in the leaf axils, small pale structures that detach easily and grow into new plants. Oxalis shares this frustrating bulbil-based reproduction, making both weeds exceptionally persistent. These bulbils can be spread on boots, tools, or by animals moving through infested areas. Deer have been identified as major spreaders, carrying bulbils in their hooves along woodland trails.
The plant can also set seed, though this is less common in UK gardens. The seeds are viable and add to the soil seed bank, providing yet another route for reinfestation.
The real challenge is timing. Lesser celandine is only visible above ground from around February to May. By early summer, all top growth has died back and the plant exists only as underground tubers. You cannot treat what you cannot see, so your window for control is extremely narrow. Wild garlic presents a similar timing challenge for gardeners.
Identifying Lesser Celandine
Lesser celandine has distinctive glossy, bright yellow flowers with 8-12 narrow petals that appear star-like. The flowers open in sunshine and close in dull weather. Beneath the flowers, three green sepals are visible on the underside.
The leaves are dark green, kidney to heart-shaped, and appear on short stalks in a low rosette. They often have a slightly waxy appearance. The entire plant grows only 10-20cm tall.
Don’t confuse lesser celandine with marsh marigold (Caltha palustris), which has similar yellow flowers but grows taller, flowers later (April-June), and doesn’t produce tubers. Greater celandine (Chelidonium majus) is completely different despite the similar name. It’s a tall plant with four-petalled orange-yellow flowers and orange sap.
Creeping buttercup also has yellow flowers but has deeply divided leaves quite unlike the solid heart-shaped leaves of lesser celandine. Buttercup flowers have five petals rather than the eight or more seen on lesser celandine.
Hand Removal
For small infestations, careful hand digging offers the best chance of eradication. The key word is careful. You must remove every single tuber, and they detach from the plant extremely easily.
Use a trowel to excavate around each plant, lifting a generous amount of surrounding soil along with it. Don’t shake soil from the roots as this scatters tubers. Place the entire plant and soil directly into a bag for disposal. Sift through the remaining soil in the hole to find any tubers you may have missed.
Never add lesser celandine to your home compost heap. The tubers survive typical composting temperatures. Put them in your council green waste bin where industrial composting reaches temperatures high enough to kill them, or bag them for landfill.
Clean your boots and tools thoroughly after working in an infested area. Tubers and bulbils cling to mud and can be transported to clean areas of the garden.
Chemical Control
The RHS notes that weedkillers available to home gardeners aren’t particularly effective against lesser celandine. The underground tubers are largely unaffected by chemicals applied to the leaves, and the plant’s brief above-ground period limits treatment opportunities.
That said, glyphosate applied persistently over several seasons can weaken and eventually exhaust the tuber reserves. The critical timing is late winter to early spring, when leaves are fully developed but before flowering begins. This targets the plant when it’s actively growing and moving energy between leaves and tubers. For the toughest infestations, the strongest weed killer available gives you the best chance.
Apply glyphosate on a dry, still day when temperatures are above 10°C. Spray in the evening to reduce evaporation and give maximum absorption time. Coat leaves thoroughly with a fine spray. One application won’t be enough. Plan for repeated treatments over two to three years, targeting new growth each spring.
For a chemical-free approach, horticultural vinegar can burn back foliage, though it won’t kill the tubers and requires repeated applications.
Avoid mowing areas with lesser celandine. The mower spreads bulbils across the lawn and contaminates grass clippings, potentially spreading the plant to wherever you use the clippings.
Smothering
Where lesser celandine covers large areas, smothering may be more practical than hand removal. Cover infested ground with cardboard, then add at least 15cm of bark mulch or wood chips. Leave in place for at least two growing seasons to exhaust the tubers.
This approach works best in areas you can take out of cultivation temporarily. The mulch needs to be thick enough to completely exclude light. Any gaps allow tubers to regenerate. Ground elder responds well to the same smothering technique.
For beds you want to keep planted, dense planting helps suppress lesser celandine. The weed prefers open ground and doesn’t compete well when shaded by established perennials. Fill gaps in borders with vigorous ground cover plants to reduce available growing space.
Living With Lesser Celandine
The RHS takes a pragmatic view of lesser celandine. Because the plant only appears briefly in spring and doesn’t tend to outcompete established perennials, many gardeners choose to tolerate it rather than fight it.
In wildlife gardens, lesser celandine provides valuable early nectar for emerging bees when few other flowers are available. The fleeting display of yellow flowers is genuinely attractive. If it’s not causing problems in your vegetable beds or crowding out choice alpines, you might decide the effort of eradication isn’t worthwhile.
Control efforts are most justified in vegetable gardens, alpine beds, newly planted areas and anywhere you’re trying to establish plants from seed. In these situations, the dense spring growth can smother young plants before they get established.
Frequently Asked Questions
Why does lesser celandine keep coming back?
The plant survives underground as tubers that remain dormant from May to February. Unless you remove every tuber, new plants emerge each spring. Tubers can persist in soil for several years, so even a single missed tuber means continued problems.
When is the best time to treat lesser celandine?
The only window is February to May when the plant is actively growing. The best timing for herbicide is late winter to early spring, before flowering but when leaves are fully developed. By June, all top growth has died back and there’s nothing to treat.
Is lesser celandine the same as buttercup?
It belongs to the buttercup family (Ranunculaceae) but is a different genus. Lesser celandine has heart-shaped leaves and flowers with 8-12 petals. Buttercups have divided leaves and flowers with exactly five petals.
Is lesser celandine poisonous?
Yes, it’s mildly toxic if eaten raw. The plant contains protoanemonin which can cause skin irritation and is harmful to grazing animals. Cooking destroys the toxin, and historically the leaves were eaten as a spring vegetable after boiling.
Should I dig out lesser celandine or spray it?
For small patches, careful digging to remove all tubers is more effective than spraying. For large infestations, a combination approach works best: reduce the population with glyphosate over several seasons, then hand remove survivors.
Lesser celandine tests your patience, but control is possible with persistence. Target the brief spring window when plants are visible, remove or treat what you can, and repeat the process for several years. For large areas, consider whether the effort is justified or whether you can learn to appreciate this fleeting spring wildflower. For similar deep-rooted challenges, see our guides to green alkanet and docks.
