Prepare the area by digging over the soil and removing any weeds. Dig in plenty of well-rotted garden compost or manure and, on heavy soil, add coarse sand or grit to improve drainage.
Cut a piece of weed-suppressing membrane to fit the bed or border. For larger areas, you’ll have to join several strips together. Leave a generous overlap along each edge and pin securely in place.
Position your plants on top of the membrane. (Presoak container-grown plants in water for at least an hour.) Check that you have left enough room for each plant to spread to its full width. Using sharp scissors, cut a large cross in the membrane directly under each plant and fold back the flaps. Make it big enough to allow you to dig a good-sized planting hole.
Take each plant out of its pot and lower it into the hole: it should sit at the same level as it was in its pot. Fill in around the root ball with soil, then firm with your heel or hand.
Tuck the membrane flaps back around the plant stem. Pin the membrane in place if needed to close any gaps, taking care not to damage the root ball. Water thoroughly.
Spread a layer of gravel mulch, about 2–3 in (5–8 cm) thick, over the membrane. Be generous, to prevent the membrane from showing through, and level with a rake. Water around the plants regularly until they are established, using a gentle spray from a watering can or hose to avoid dislodging pockets of gravel. If any weeds get through, they should be easy to pull out.