The root of 3; Three plants that look good together: Nepata Cynara cardunculus Elaeagnus angustifolia

Forget the cold winds of March and cast your mind forward to the height of summer, when this grouping will be at its best - lush foliage in soft tones of grey and silver. It needs sun, well-drained soil and elbow room.

The star of the show is the impressive Cardoon - Cynara cardunculus - a close relation of the Globe artichoke and one of the most magnificent of the herbaceous perennials.

From a fleshy root-stock, it erupts in spring into a mushroom cloud of foliage. Elegant, silver-grey leaves, pointed and deeply incised, reach more than 3ft long. The towering stems are stout and woolly and, with more leaves along their length, climb 8ft into the air.

In late July or August, these are topped by flowers: branched sprays of huge, purple-blue, nectar-filled thistle heads. If you cut them just before they flower, they will last well indoors and can be dried for use during the winter.

In colder parts of Britain, keep the Cardoon well covered in winter, particularly until your clump is established, for they are not completely hardy.

There are legions of plants that complement the Cardoon, but some of the most effective are others with grey leaves. Try the Oleaster or Jerusalem Willow - Elaeagnus angustifolia - which has been cultivated in Britain since the 16th century, yet is seldom seen.

Its botanical name, Elaeagnus, comes from the name given to the wild olive by the Greek physician, Dioscorides; its common name, Oleaster, comes from the Latin word, oleum, an olive. Both refer to the colour of the plant's long willowy leaves - bright silver in the spring, ageing to silver-grey. Unlike the olive, the Oleaster loses its leaves. But they turn yellow in the autumn before falling.

Place this plant next to the Cardoon for a variety of grey and silver tones and a marked contrast of leaf shapes.

The Oleaster flowers in June: slender, silver-yellow funnels, with a scent greater than their size, are followed by small, oval, dull-orange, edible fruits. It grows quickly, easily reaching 15ft in height, but it can be pruned in the spring if you need to keep it in check.

To lap around the feet of these two giants, plant the humble Catmint - Nepeta - but choose its large form, Six Hills Giant, which grows to about 3ft high.

Its small, felty, grey-green leaves add another tone to the scheme, as well as a different leaf scale. Best of all, its lavender-blue flowers continue from June until autumn.