Daylilies

Most daylilies do exactly what they say - flower for one day only - but don't let that put you off, because new buds keep developing, producing a long run of summer flowers. The colour range is huge, running from white, yellow and orange to purple and rich darkred.

Most hemerocallis species come from the Far East where they've been cultivated for thousands of years - the unopened flower buds are a Chinese delicacy. The yellow H. lilioasphodelus was one of the first Chinese species to be introduced to Europe during the 16th century. Flower shapes now vary from singles and doubles to spidery petals, ruffled edges and almost flat-faced blooms; the simple elegant trumpet shape remains a big favourite.There are hundreds of varieties that are good for a lively burst of border colour.

Site and soil preferences: Most varieties prefer soil that doesn't dry out completely in summer and, although they need plenty of sun, red varieties are more successful in a light woodland setting that prevents any petal-scorching. Daylilies also look good planted by a pond or streamside, but only if the soil's not too soggy and the variety is one of the older, more robust varieties.

Division: Plants growing vigorously for a number of years can become congested and, as a result, start producing fewer flowers. If this happens, divide them in spring and replant the sections in enriched soil to give them a new lease of life. Separate the lush leaves emerging from the fleshly roots to create new plants. Pot up and allow the new plants to establish.

Feeding: Apply a sprinkling of high-potash fertiliser in spring, followed by a mulch of compost to encourage strong growth and plenty of flowering stems.

Diseases:

The daylily escapes most pests and diseases, but keep a look out for any flower buds that become abnormally swollen and fail to open. This will most likely be caused by the hemerocallis gall midge, a tiny insect whose grubs feed inside the unopened buds. As the pests are well protected from sprays, the only remedy is to pick off and destroy any buds that are affected. Because the main egg-laying period is in late spring, the late-flowering varieties often escape damage.