How to Edge Santolina

Plant santolina shrubs to create an edge in the garden. Choose naturally dwarf cultivars that mature 6 to 16 inches tall and wide, such as Weston and Pretty Carol. These will require much less trimming maintenance. Plant dwarf cultivars six to 10 inches apart, but larger-maturing selections 18 to 24 inches apart.

Trim back all branches and stems of the santolina in the edging row in spring. In U.S. Department of Agriculture plant hardiness zones 8 and 9, schedule trimming for early spring, such as March or very early April. In zones 6 and 7, time it for midspring, anytime in April.

Cut into the santolina from the outer branch tips first, using a scissorlike pruning shears. Snip off the branches little by little -- in increments of 1 to 2 inches at a time -- to shape the shrub and reduce the size. You may reduce branch tips back until 1/2 to 1 inch of lower alive leaves remain. Try to avoid cutting back so severely that only bald, dead-leaved stem bases remain.

Trim the new growth that sprouts back from the spring trimming again in early or midsummer. If you want the santolina edging to remain low and tidy, trim every month, removing an inch of new growth, to help keep the plants compact. However, repeat trimmings into summer will likely remove tissues that would produce the flowers.

Maintain the santolina edging as needed with light trimmings until Labor Day. It's better to have lower branches wider than upper branches on the plant, as this ensures sunlight reaches lower tissues. When looked in side profile, the trimmed and well-maintained santolina edge with look like a rounded A, not like a V. This reduces the chances of ending up with plants with leafy tops but naked, brown plant bottoms.

Clip off old flowers once they begin to wane and dry, if any form based on the frequency of your pruning in summer. Trim the upright flower stems back at a height that is even with the general form of the row of plants. Clipping off the dead flowers greatly improves the appearance of the edging.