Jobs to do this weekend

Sweet peas need training and tying to their supports to encourage them to climb and make a good display. Spreading and trailing plants such as the annual Lobularia (sweet alyssum), and the perennials Alyssum and Aubrieta, can become tatty. Trimming them back after flowering encourages fresh growth and new flowers. Hoe borders to prevent annual and perennial weeds from spreading and seeding themselves. Liquid feed plants in containers every two to four weeks. Aphids can multiply rapidly. Remove early infestations by hand to prevent the problem getting out of hand. Protect sweet pea plants in particular, as they can get sweet pea viruses. Continue to protect lily, delphinium, hosta and other susceptible plants from slugs and snails. Prune spring-flowering shrubs such as Japanese quince (Chaenomeles), Choisya and Ribes after flowering. Remove one stem in three from Kerria and Spiraea ‘Arguta’, and shorten the other flowered stems to a suitable sideshoot. Evergreens such as Viburnum tinus can also still be trimmed. Prune wall-trained pyracanthas, removing any shoots coming out from the wall, and shortening other new growth to about 8cm (3in). This encourages spur formation, and increases flowering. Remove blanket weed in ponds by twirling around a rough stick. Skim off floating weeds such as duckweed with a net. Leave weeds on the pond side for 24 hours to allow trapped creatures to return to the water.