Many Penstemons come into their own in early autumn and flower prolifically until the first frosts. Whether added to the border during spring, used as gap fillers in June or planted as a quick fix in September, this versatile plant will obligingly produce one sumptuous spike after another, adding a touch of late splendour to the garden. Never cut Penstemons down in the autumn. Leave all the growth intact and wait until late April or early May. Penstemons thrive in sunny positions and tolerate dry conditions once established.