Some shrubs, trees and plants don’t set seed easily and are best propagated from part of the original plant that can be persuaded to develop roots.
Plants that can be propagated from stem cuttings include delphinium, geranium, pelargonium, chrysanthemum, dahlia, fuchsia and many shrubs. Stem-tip cuttings need to be cut to below a leaf joint and the bottom leaves removed. Dip in to a hormone rooting powder and push around the edge of a pot filled with a seed and cutting compost. Keep warm and moist. Basal cuttings from delphiniums should be trimmed from the mother plant and pushed into the compost.
Some leaves can root and produce a new plant where the veins of the leaf have been cut. Cut the veins on the underside of a Begonia rex leaf and pin this down onto a bed of seed and cutting compost.
New plants of phlox, anchusa and oriental poppy can be achieved from 3cm (1in) of fleshy root buried 1cm below the surface of a seed and cutting compost.
Perennial plants that spread outwards after a few years will need to be split into smaller sections and re-planted so that each has it’s own space. Dig up the plant and shake off as much soil from the roots as possible. Push two garden forks back to back into the clump to prise the roots apart. When you have small enough sections, plant in enriched soil at a similar depth to the original plant.