Guide to hardy plants

In part two of a series, we look at how to look after your hardy herbaceous perennials and continue with our comprehensive ABC of suitable plants

MOST hardy plants can be planted most conveniently with a short-handled trowel, but a small spade may be better for large plants. Holes should be large enough to accommodate the roots comfortably and to permit the crown of the plant, where shoots join roots, to be just level with the surface. Fine soil should be returned around the roots and be made firm with knuckles, the trowel handle, or foot.

March and April are safe months for planting almost everything. On light soils, planting may commence in February and may also be resumed in October, but on wet soils autumn planting can be risky.

Some hardy plants make so much growth that they crowd themselves out. The quality of flowers can be improved by thinning out the young shoots, such as those of delphiniums and Michaelmas daisies.

In many instances the firm young shoots removed can be used as cuttings and will form roots readily if inserted 1in (2.5cm) deep in sandy soil in a box covered with a sheet of glass or polythene film. Cuttings are particularly successful for increasing delphiniums, scabious, and anthemis.

Supporting tall plants

Thinning is done in April and early May. Cuttings inserted then should be well rooted by midsummer, when they can be planted out in good soil to grow on into sturdy plants.

Many hardy plants are entirely self-supporting, but some of the taller kinds do need staking, especially in exposed places, and some shorter thin-stemmed kinds benefit from a little assistance to hold up their heavy blooms.