Buttercups - the ranunculaceae
Has a cheerful yellow tinge spread across the tops of your pasture in the last month? If so, it’s just the various buttercups telling you “Here we are again!"
Buttercups often flourish in dairy pastures, because the cattle won’t eat them. They also do well in damp or swampy places, and are early colonisers of waste areas and roadsides.
They come in different leaf shapes, varying heights, and some are perennial and others annual. Some are toxic to all grazers, while others will be eaten by sheep but not cattle. So knowing which types are growing on your place is useful to know.
Often the most prevalent is Creeping Buttercup (Ranunculus repens). This is the one which creeps through the grass, putting down roots at intervals. The leaves are hairy, divided into three, with the central one on a short stalk. Often there are pale or silvery patches on the leaves. It flowers less effusively than other varieties, but can render large patches of pasture inedible, and as a perennial it’s always around. It is often found in orchards also, because it is tolerant of many of the chemicals used there. And mowing doesn’t help much because it just grows sideways into unmown strips. In pasture MCPA usually gets rid of it.
Around October/November the annual Hairy Buttercup (Ranunculus sardous) reappears. This starts out as a rosette with three part circular and shiny leaves, which gradually become more divided and duller in colour. The stems are hairy. It flowers prolifically, thus ensuring a goodly supply of seeds are spread for the following year’s crop. On small blocks one can assume a semi-permanent stooping position and pull them out. The rooting system is small and compact, and those which grow tallest are easiest to pull out. Again, MCPA is probably the most useful herbicide to use.
A much taller species is Giant Buttercup (Ranunculus acris) which can grow up to 1m in clumps from a single crown at ground level. Leaves on this are much more segmented, almost lacy, and the flowering stalks are many branched with lots of flowers per plant. While sheep will eat it, cows won’t and it is proving to be a problem in some dairying areas where it can spread across whole paddocks. It has a long flowering season (Nov-Apr), and in some places has developed resistance to phenoxy herbicides like MCPA and MCPB, so check with your Regional Council for its status in your area as it may be subject to local Pest Plant Management Strategies. It is particularly prevalent in Taranaki, Nelson Bays and near Woodville. Newer sprays such as Harmony and Preside which use different chemicals will get rid of it, and Uptake Spraying Oil is recommended to be used with Preside for best effect. Spraying is most effective before it starts flowering.
Others, which are poisonous to stock are Spearwort (Ranunculus flammula) which has long pointed leaves but buttercup flowers, Celery Leaved Buttercup (Ranunculus sceleratus) which has fleshy, shiny leaves and favours drains and other wet places, and the native Waoriki (Ranunculus amphitrichus) which is creeping, hairless and also likes wet places. Waoriki is particularly toxic, with many poisonings attributed to it.
The term ranunculus means ‘little frog’ because of buttercups’ fondness for wet places. So in areas with high rainfall and lots of damp patches, there’ll probably always be buttercups of some sort.