THERE are so many primroses from which to choose these days garden centres are awash with them for any situation, from the bog garden to the rockery. But I don't think you can beat the deep purple varieties as a companion to the many delicate dwarf narcissi you can find for the rockery or container.

Pretty double varieties include Primula Blue Sapphire and P. Eugenie.

Primroses like damp, humus-rich soil in partial shade and are useful for ground that will be shaded later in the year, but not where they will dry out.

Other good combinations include Sue Jervis, a double pale peachy pink which looks good with variegated brunnera or pulmonaria. Try matching the deep red double Corporal Baxter with the burgundy foliage of Helleborus x sternii.

Primroses should be lifted and divided every other year for continued good flowering. When replanting, add some bonemeal to the soil. They should be mulched in spring, deadheaded when flowers fade, and watered in summer.

What to do this week: - Sow hardy annuals in a cold frame or unheated greenhouse - Sow tender bedding plants in a heated propagator or in trays on a warm windowsill - Lift and divide congested clumps of perennials - Plant out bulbs grown for indoor use which have finished flowering - Mulch beds and borders while the soil is moist to reduce the need for watering and to keep down weeds - Prune roses, removing decaying, old and thin spindly wood - Sow heliotrope in seed compost and germinate in a temperature of 20C (68F). It will provide a filler and background among other bedding plants - Sow summer spinach for harvesting in May - Lightly trim winter-flowering heathers which have finished flowering - If the ground is workable, move deciduous trees and shrubs and plant new bare-root plants before they start into growth - Add another layer of stone chippings to the rockery to stop your alpines getting waterlogged.