Yarrow, achillea

Achilleas are cheery border, wildflower and rock garden plants with flattened heads in a range of bright colours, from white to lemon, pink and red.

A. filipendulina : a stately plant with solid heads of golden yellow. It can grow up to 2m (6.5ft) and its two cultivars, 'Gold Plate' and 'Cloth of Gold' , are equally popular. All the A. filipendulina varieties last for a reasonably long time and are successful in dry soils. The Royal Horticultural Society (RHS) has given 'Gold Plate' and 'Cloth of Gold' its Award of Garden Merit (AGM).
The current range of hybrids between A. filipendulina and A. millefolium come from Germany, where they thrive on cold winters. Many of the hybrids have flowers that fade gracefully, so the plants show several colours at once. The orange-red 'Walther Funcke' fades well, as does the paler 'Forncett Fletton'. 'Lachsschönheit', which means 'Salmon Beauty', begins as salmon-pink in colour, but fades to pale yellow, and then pale pink. 'Fanal', formerly called 'The Beacon', has attractive, dark scarlet flowers that fade to pink. The RHS has handed 'Lachsschönheit’ its AGM.
A. grandifolia : is a long-lived plant with white flowers over deeply divided leaves.
A. 'Moonshine': a nice combination of scented, rich yellow flowers set against dark green leaves.
A. ptarmica : the vigorous sneezewort gives a summer-long show of white flowers, but it can be invasive and is best grown in wild gardens.
A. Summer Pastels Group : ideal for instant flowers, it blooms just a few months after sowing.

Site and soil preferences

Provide good sun and light, sandy soils. They almost invariably die over winter if there is any clay in the ground.

Deadheading

Achilleas flower from June to July, and sporadically in August and September if the plants are deadheaded.

Cutting back and dividing

Some varieties stand a better chance of surviving if they're cut back hard after flowering. Divide and rejuvenate the older plants in autumn or spring, although these new plants usually have inferior flowers to their parents.

Planting associations

The colours of achilleas lend themselves to hot, Mediterranean colour schemes.

The flattish, umbel-shaped flower-heads are complemented by the spikes of the yellow mulleins and salvias. Some ornamental grasses and sedges, such as carex, also combine well.

Achillea with the blue and violet salvia hybrids, such as Salvia x sylvestris 'Blauhügel' or 'Mainacht', make a classic combination.