It’s simply a matter of collecting the material, preparing it and placing it in a suitable environment.
In the greenhouse, a streptocarpus Polkadot Purple is mature enough to take some leaves for propagation.
It’s difficult to walk past such plants when they’re almost shouting out for the kind of attention that will be of benefit to the gardener so the propagating box works overtime throughout summer. When it’s full we improvise with mobile propagators in the form of deep trays with plastic, domed tops.
The ideal rooting medium is light, open and gritty, but capable of retaining moisture. I prefer sieved compost from the base of a garden waste composting system as the bulking agent. This is mixed 50-50 with sharp sand or perlite.
The best time to collect stem cuttings from outdoor plants is early morning. Dress them by removing some lower leaves, then immerse in water for an hour or two so they’re fully turgid.