The Gardening Year for Perennials

Spring

Start planting or sowing hardy perennials in prepared ground in early spring, as soon as weather conditions permit. Herbaceous perennials may be lifted and divided at this point. Feed and mulch established perennials and water new plants as necessary.

In mid-spring, remove dead growth of half-hardy plants and cut back shrubby perennials. Any tender plants may be brought outdoors on mild days to harden off; bring them under cover if frost threatens.

In late spring, thin out dense shoots and 'stop' (pinch out) any plants that need to be encouraged to produce side shoots and develop a bushy habit. Provide supports for tall plants or climbers. Repot or top-dress plants in containers.

Summer

In early to mid-summer, collect and sow seed of early-flowering perennials. Keep container grown plants well watered, especially in hot, dry weather. Dead head spent flowers throughout the season to keep flower production at its strongest, unless seed is required. Take stem tip cuttings of tender perennials for propagation.

Autumn

Continue to deadhead flowering plants unless the seedheads are needed for decorative purposes, or for the seeds themselves. Cut back hardy plants to the base; however, in cold areas, this foliage should be left to provide the plant with some protection against frost and wind. Divide old or congested clumps of perennials so that the roots can re-establish before the winter.

Plant hardy, bare-root and container-grown perennials in prepared ground, and transplant any established plants that need to be moved. Protect tender perennials from frost; insulate their crown and roots with straw and hessian, use a cloche or bring under cover over winter.

Winter

Tidy the garden and clear away plant debris. Make sure that non-hardy perennials are protected from the frost.

If weather conditions permit, plant hardy perennials in late winter. Seeds of slow germinating plants may be grown in a heated greenhouse or conservatory. Soft perennials that come into leaf early, such as blue cowslip (Pulmonaria) and leopard's bane (Doronicum), may be lifted and divided.

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