Knotted Cranesbill (Geranium nodosum) is not a spectacular plant but there's a lot to be said for it. For one thing it will grow in deep, dry shade and will flower there. The flowers are not prolific at any one time but G. nodosum flowers for months from early summer to mid-autumn. The foliage is deciduous but present in at least three seasons and arguably semi-evergreen here in London. The leaves take on beautiful russet red tones in autumn.

 It spreads- which is a good or bad thing depending on how you look at it. As one of the gardeners at the South London Botanical Institute said to me: "If you've got it you will never be rid of it". I look on that as a good thing. In fact I got a quantity of the species from the SLBI.

 One of the their beds was becoming infested with G. nodosum and I was asked to weed it out when volunteering there earlier in the year. Fair exchange is no robbery so I kept all the "weeds", potted them up and planted them round the garden last week.