One whole side of my garden has been taken over by a herbaceous plant,
apparantly starting off with just two clumps given by my neighbour to the
previous owners a few years ago. In fact, a lot of the gardens here have
this plant and I've seen it at the roadside as well. It's a couple of feet
tall, with spikes of bright yellow flowers, the flower spikes themselves
being about a foot long. The flowers have five petals and look like small
yellow stars. It started flowering a few weeks ago and is still going
strong, though some of the earliest ones are now starting to go a bit brown.
Any ideas?