In the mild British climate the real winners are ‘weedy’ species which can grow at low temperatures. Amongst the most problematic for gardeners are native grasses, particularly aggressive species of rough pasture, and creeping buttercup. Such is their ability to grow at any temperature above freezing, I reckon these guys can often grow 365 day a year. Anyone with a herbaceous planting that does not have a thick layer of mulch will begin to notice around this time of year that there is often a haze of young grass seedlings, or clumps of grass which you did not notice the last time you looked at the border (which was probably November) have begun to grow and spread. Most alarming of all is the relentless march of creeping buttercup, as it extends its runners out of the clumps of perennials where it often settles down, inconspicuously for the winter (or since when you last thought you had weeded thoroughly). In the milder and wetter parts of Britain bare soil in borders can be practically covered in this stuff, practically while your back is turned.
What to do about it?
First – ask yourself how much a problem this really is. Look at the plant – it may spread like a virus, but it doesn’t grow very tall. In fact so short is it, that by the time most herbaceous plants get going in May, they will soon overtop it and shade it out. Meanwhile the yellow buttercups in April are quite pretty – an added bonus. So, it may be a case of live and let live – dense planting of medium to tall, or very spready herbaceous perennials will outcompete the yellow monster – and peaceful co-existence will be the result.
Amongst smaller plants or where you want to reduce competition, such as amongst fruit bushes or new plantings, you will need to control the beast. The best way is to leave it, until it really begins to spread, with lots of nice healthy foliage. Then get out the Roundup ®. The herbicide will spread back and kill the base of the plants, which may be a good 20-30 cms from where you have treated it. Winter spraying is slow to take effect – it’ll be a few weeks before that yellow and wan look begins to spread, the yellow and wan look which brings an instant smile of gratification to the gardener’s face. There is something insolent about creeping buttercup, the way it so suddenly takes advantage of our winter lack of interest in the garden to make so much progress. Get it now, before bulbs have begun to emerge, let alone anything herbaceous and you can minimise its impact for the rest of the year, and even admire the pretty yellow flowers of the survivors. You will never get rid of entirely so you might as well stand back and admit they’re pretty.