A superb geranium for any border, 'Plenum' produces the most beautiful violet, double, ruffled flowers set on a backdrop of deep-green foliage - a real top perennial Geranium What's really special about 'Plenum', also known as 'Birch's Double', is that the glossy green foliage almost magically changes colour in the autumn to a fiery orange-red - so not only do you get wonderful flowers from June, but foliage interest too. It's low growing, reaching a height of about 30cm so is ideal for use as groundcover and also perfect for pots and containers in smaller spaces. It is easy to manage, tolerating most soils and with a hard cut back after a first flush of flowers in June and July, you'll likely get a second round well into autumn.