Another strong spring colour (I’ve already touched upon Berberis darwinii in particular and Forsythia briefly) and this shrub too can be a bit of a forceful character. Quite tenacious, it can thrive where other plants would give up and it suckers quite freely (the looser the soil, the greater the spread). If it does get out of hand, overgrown or unkempt, simply cut it to the ground after flowering.
Pleniflora is a double form, with almost ball-shaped, golden yellow flowers. Very vigorous and suckering with a vengeance! Its blooms coincide with hesperis and aquilegia. This example is growing in my less than hospitable front garden, on thin, poor soil (see the Victorian builders!) – the remnant of a larger plant I was forced to dig out before it overtook all. Very glad some of it survived.