They need what might be described as good kitchen-garden cultivation. Their colours today embrace white, cream, pink and purple besides the most valuable of all the splendid pure blues. Paeonies also need all the sun, air and good cultivation they can get, and only to a lesser degree do they contribute the glory of their bowls and bosses of magnificent colours. Some of the single-flowered species open in late spring; pale yellow Paeonia mlokosewitschii, magenta P. arietina, pure white P. emodi and others. They appear before the old double red P. officinalis which is followed by a huge range of doubles and singles descended from P. lactiflora, from white through pink to darkest crimson. The foliage of all is large-lobed and lasts in beauty for most of the summer. Few people today plant a border of Michaelmas daisies, partly because they suffer from mildew. But it is as well to add here and now that all highly developed and selected strains of plants are more troublesome when it comes to pests and diseases than are nature's wildings. And so, leaving special areas of the garden set aside for carnations and delphiniums, paeonies, dahlias and the like we will return to the perennials which can be grown in mixture with shrubs and other plants in varying situations and with varying effect. TALLER PLANTS Taking them as a whole perennial plants are of less weighty calibre than shrubs and, of course, almost all die to the ground every winter. Even so we should bear in mind that there are a few very tall plants-of 6ft(2m) or so-which in their season can dominate everything. For instance, the magnificent foliage and spires of yellow of the garden plant known as Verbascum vernale-a mullein of great value, starting to flower in June. Also for early summer there is that huge cloud of white from Crambe cordifolia and the light yellow scabious-flowers of Cephalaria tatarica. Soon after these the lobed glaucous leaves of Macleaya microcarpa appear, borne all the way up the stems which support the sprays of tiny flowers giving the name of plume poppy. This is a rather invasive plant; the closely related M. cordata is far more compact, with white instead of flesh-coloured flowers. And in August there are the giant Rudbeckia laciniata 'Golden Glow' and R. nitida 'Herbstsonne', daisies of bright brassy yellow, the one double and the other single. In September come the white Hungarian daisies of Chrysanthemum uliginosum, so telling when used with the spires of lavender-blue of Aconitum carmichaelii var. wilsonii 'Barker's Variety', a monkshood of special excellence. But these, together with the tallest of big red hot pokers, certain cimicifugas and the goat's beard, Aruncus dioicus (A. Sylvester), are only for large gardens-or at least large borders. As a general rule it will be found that the height of plants used should not exceed half the width of the border. Let us then return to the plants which achieve iff to 4ft(30cm to 1.