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.
Get to know spirea
- 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.
Make spirea part of your garden plan
- 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.
Choose a variety
- 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.
Prepare the ground
- 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.
Help them flourish
- 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.
Prune during the season
- 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.