Expert advice for growing healthy spirea

Spirea is a versatile and hardy plant that can enhance the look of any garden. Here are some expert tips on getting the most from your spirea plants.

• Spireas are a varied group of plants grown for their attractive foliage, graceful habit and charming flower clusters.
• They have small, slightly fuzzy flowers in white, pink and red.
• While there are many species and cultivars, there are basically only two types: those that bloom in spring to early summer and those that bloom in summer.
• Both share a care-free nature and are very easy to grow.

• Spireas are also easy to use in the landscape.
• They make a valuable addition to foundation groupings, especially when planted among shrubs with dark foliage.
• Mound-forming types make a neatly shaped filler for shrub and flower borders, or can be massed as a ground cover.
• Those with arching habits make graceful specimens and are dense enough to be grouped into a hedge.

• Both bridalwreath and Vanhoutte spirea have 1.5- to 1.8-metre-long arched stems studded with white flowers. They're also quite cold tolerant, being hardy to Zone 4.
• Japanese spirea is a compact, mounding summer blooming shrub. The plants are covered with airy clusters of dusty pink flowers.
• Varieties grown for their flowers include 'Anthony Waterer,' a favourite with crimson blossoms, and 'Shirobana,' which produces white and rose flowers in the same cluster.
• Other Japanese spirea are valued for their foliage. 'Goldflame' has yellow leaves contrasting with pink flowers. All are hardy to Zone 3.

• Spirea grows quickly when planted in early spring.
• Amend planting holes with organic matter, like compost or leaf mold, and set plants at the same depth at which they grew in their containers.
• In alkaline soils, also work a small handful of garden sulphur into planting holes.
• Spirea needs slightly acidic conditions. If the pH is too high, green-leaved types will develop yellow leaves.

• After planting, cover the plant's root area with an eight centimetre (three inch) layer of mulch. This reduces evaporation from the soil.
• Water as needed to keep it barely moist the first season.
• Once established, bridalwreath types need no special care.
• Japanese spirea benefits from a light feeding with an organic or timed-release, balanced fertilizer each spring.
• Aphids may occasionally infest plants, but these sap-sucking insects can be knocked off foliage with a strong spray of water. Or, apply insecticidal soap as directed on the label.

• Neither type of spirea demands attentive pruning, but it's important to preserve flower buds when grooming the plants.
• Spring bloomers set flowers on old wood, so the best time to prune is after the flowering period has ended.
• To maintain its natural arching shape, prune out old woody stems near the base of the plant.
• Thin crowded stems by cutting them back to various lengths for a more natural appearance.
• Japanese spirea blooms on new wood, so you can prune as much or as little as you like in early spring.
• In cold climates, prune winter-damaged stems to the ground.

Spirea are a hardy and versatile plant that can perform many different functions in your garden. Be sure to find a variant that works for your garden, and keep it well-maintained throughout its life. If you do, the results could be well worth the effort.