Ranunculus repens L.
Perennial Broad-leaved Weeds
A native perennial common in damp meadows, pastures and gardens throughout the UK. It is the commonest of the buttercups and is an efficient colonist of areas disturbed by man and a troublesome weed of arable land. Creeping buttercup occurs on a wide range of soils but forms large colonies on wet, heavy land. On ridge and furrows, it often occurs in a band along the bottom of the furrows. It can withstand trampling and compaction and is common in gateways and on paths. It can tolerate both waterlogging and a moderate drought.
Plant morphology and growth vary with habitat and grazing pressure. A number of varieties have been described that differ in growth habit and flower colour. Stolon formation is linked with soil fertility and vegetation cover. Clones vary in leaf number and this determines the number of primary stolons that are produced. Some plants spread widely others remain relatively compact,
Although it is usually avoided by stock creeping buttercup is more palatable than the other buttercups and may be grazed. However, it can cause diarrhoea in sheep and cattle. Creeping buttercup is said to deplete the land of potassium and may have an allelopathic effect on neighbouring plants.
Creeping buttercup flowers from May to August. Sometimes the plants do not flower in the first year or flowering is delayed until later in the year, up to October. The flowers are insect pollinated, some selfing occurs but cross-pollination predominates. Not all plants flower and those that do so may have only a few flowers each producing 20-30 seeds. A flowering shoot may yield 140 seeds and the average seed number per plant is 687. Plants from ruderal habitats tend to flower more freely perhaps because seed production is more beneficial in a disturbed situation.
Ripe seeds are highly dormant and may need a period of after-ripening. Seedling emergence can occur sporadically throughout the year but the main periods are from February to June and August to October. Most seedlings emerge from 5 to 30 mm deep in soil. Adequate soil moisture is important for germination and early growth. Seedlings rarely develop in established vegetation but on open and disturbed land they often occur in patches or clumps. The seedlings are unaffected by frost.
Creeping buttercup is a very variable plant. It has a short swollen stem base, long stout adventitious roots and strong leafy, epigeal stolons that root at the nodes. The stolons begin to develop around the time of flowering. In open and fertile sites, the stolons are long and well branched to ensure rapid colonisation. In close turf the stolons are few. It normally has a creeping habit under intense grazing or mowing but makes erect growth in taller vegetation. In dry conditions creeping buttercup flowers and sets seeds, in wet conditions it tends to increase by runners.
Daughter plants form in the axils of the stolon leaves. The stolon internodes wither and rot away leaving the daughter plants as independent units. The parent plant dies after seed ripening and the daughters overwinter as leaf rosettes. In spring new leaves develop and later, just prior to flowering , buds low down on the rosette grow out into stolons that root at the nodes and produce a new crop of daughter plants. Stolon production continues into the late summer.
Persistence and Spread
Seed longevity in soil is said to be 5 to 7 years but seed recovered from excavations and dated at 80 years old is reported to have germinated. Seed buried in undisturbed mineral soil at various depths retained around 50% viability after 20 years. Seed dormancy enforced by soil burial leads to a high population of creeping buttercup seeds in the soil seedbank. Up to 12,000 seeds per m² to 15 cm depth have been recorded. There is considerable persistence of creeping buttercup seed in the soil under grassland. It made up 36% of the seedbank when pasture was ploughed after 22 years. The annual decay rate of seed in soil has been measured at 38%. Seeds survived 3 years in dry storage. Viability was 18% after 1 year under granary conditions.
Most seeds fall around the parent plant but birds eat some of them. Seedlings have been raised from the excreta of various birds including the house sparrow. Seeds have been found in the droppings of cattle and horses. Seeds eaten by earthworms have been recovered from wormcasts. Some rodents carry off and store the seeds. Seeds are also carried in mud on tyres and boots. Creeping buttercup seed has been a contaminant in clover, grass and cereal seeds, particularly home saved seed.
In dry conditions, creeping buttercup sets seeds but in wet conditions it relies on vegetative reproduction for spread and persistence. The stolons grow rapidly when the vegetation cover is opened up by poaching or puddling, by mole activity and wherever the grass has died.
Creeping buttercup is controlled by frequent and vigorous cultivation in hot weather. Plants damaged by a single isolated cultivation can recover. Deep ploughing may kill plants buried below 15 cm but creeping buttercup can survive shallow burial. The destruction of a grass sward, especially in spring, provides ideal conditions for rapid colonisation by creeping buttercup seedlings before a new crop is established. After ploughing it is best to clean up the land with one or more root crops before putting down to grass again.
In grassland, small patches can be removed manually. Meadows should be harrowed in spring to drag out the creeping runners. These should be gathered up to prevent re-rooting. Intense grazing prevents seed set. Mowing may reduce plant density and vigour but grazing does not. In roadside verges, the creeping buttercup population increases with cutting frequency. It is particularly favoured by cutting twice a year.
Creeping buttercup plants are attacked by a number of insects, fungi and grazing animals. Partridges, pheasants and wood pigeons eat the seeds. Chickens and geese readily eat the leaves. Creeping buttercup tolerates rabbit grazing but growth becomes more prostrate.
Updated October 2007.