All The plants in this combination are culinary herbs with deliciously aromatic leaves, but are of such ornamental value as well, that they would be worth planting even if none of them ever got within a mile of your kitchen. All come from kinder climates than our own and will appreciate well-drained soil and sun.

The bronze fennel, Foeniculum vulgare "Purpureum", is a striking, airy plant, with leaves as fine as hairs. Each summer, it makes a 6ft fountain of hazy, aniseed-flavoured, bronze-purple foliage, topped by flat, yellow flower-heads and followed by aromatic seeds.

Planted in front of the fennel, the rosemary, Rosmarinus officinalis, will make a decent-sized shrub if you let it have its head. Its branches, covered in peeling and flaking bark, form a dense, rounded mound which needs little maintenance. Prune only to keep its size in check or to tidy up its shape.

Rosemary is evergreen, so it will be around to give some structure to the garden when the fennel has disappeared for the winter. It has long, thin undersides and light-blue flowers that appear from mid-spring to early summer. Ancient and pot-bound, my rosemary began flowering in the middle of February this year, in the teeth of the gales.

The Purple sage, Salvia officinalis "Purpurascens" is also a shrubby evergreen and makes a mound a few feet high and wide. Its oval, felty- textured leaves are red-purple when young, becoming greener with age, and give the plant a striking two-tone colour scheme. The purple hues echo the colouring of the bronze fennel and the leaf shape makes a good contrast. In summer, spikes of bee-laden purple flowers rise above the foliage.

Although hardy, it doesn't much like our wet winters (who does) and sometimes succumbs to them. It also tends to get leggy with age, so cut it back hard every couple of years or replace with new plants.

To this week's "Root of 3" add a fourth. In among the foliage of the other plants, nestle a pot of ginger mint, Mentha x gracilis "Variegata". Its green, ginger-flavoured leaves are striped and flecked with gold and look particularly effective against the froth of bronze Fennel. Make sure you keep it confined to its pot, however, for mint is invasive and its roots know no bounds.

John the Gardener