Growing Spiraea (Spirea)

Pronunciation: spy-ree'-ah

This genus of deciduous shrubs includes about 80 species, all native to the Northern Hemisphere. Among them are dozens of attractive varieties that are extraordinarily well suited to contemporary gardens by virtue of their generous flowering habit and easy culture.

Light: Plant in full sun.

Soil: Spiraea grows well in average soil. Turn a healthy layer of organic matter into the soil before planting.

Watering: The key to getting your new shrub or tree off to a good start is moisture. Water thoroughly after planting, and keep a close eye on the plant over the following week. Then, give it a good soaking once a week during summer, unless rainfall is plentiful (more than 1in per week). Established plants can generally get by on less water, but most grow best if the soil remains evenly moist. Please note that more is not better. When in doubt, don't water.

Fertilizing: We recommend against fertilizing at planting time and during the first growing season in your garden. Plants need time to settle in before being pushed to grow. Most established plants grow best if fertilized with a light hand. Here at the Farm, we fertilize our specimen trees and shrubs just once -- in early spring -- with a light but even coverage of a balanced, granular fertilizer (such 5-10-10, 10-10-10, or an organic fertilizer). If a concentrated, water-soluble fertilizer is used, please follow the manufacturers' recommendations carefully.

Continuing Care: Remove dead or broken stems in late winter or early spring. S. prunifolia (Bridal Wreath) flowers on the previous season's growth and so should be pruned to shape after bloom in spring or early summer. S. japonica also flowers on new growth, so should be pruned in late winter or early spring; a light trim after the first wave of bloom often promotes a smaller second wave. To rejuvenate a mature Spiraea plant, remove about 1/3 of the oldest stems each year for three years, cutting them off at the base.