The first thing you learn when using ‘black’ plants in the garden is that they’re rarely black; dark reds, purples, and sometimes dark blues are usually the norm. Despite this, plants like Pelagonium sidoides do look virtually black in a garden setting or lower light situations.
This particular plant sometimes referred to as the African Geranium sports its flowers on wiry delicate stems combining well with its silver foliage that works superbly in summer pots. It’s not as vigorous or as big as some of the other popular pelargoniums so if mixing the two together, be aware that sidoides could be easily swamped by its more enthusiastic cousins.
Once you have a few plants you will find they are particularly easy to propagate because each stem throws up a nice rosette of leaves. These can be detached with a short bit of stem and rooted quite easily in a general purpose potting mix with or without the use of a rooting gel. Pelargonium sidoides is surprisingly hardy. We have them in a large pot as underplanting to a standard bay tree. They have remained outside for 5 winters now and come back every spring to flower until the first frosts or often later.
In The Genus Garden - Musings From Joff, Our Head Gardener