Japanese spirea (Spiraea japonica 'Anthony Waterer')

Overview

Spiraea japonica ‘Anthony Waterer’, commonly known as Japanese spirea, is a highly valued, dense, upright deciduous shrub prized for its extended bloom time and manageable size. This cultivar provides abundant, showy flowers that shift from a vibrant carmine red in the primary flush to subsequent intermittent blooms throughout summer. As a low-maintenance plant, the Japanese spirea offers excellent textural and color interest, transitioning from reddish new growth to blue-green summer foliage and hints of red in the fall.

This compact cultivar of Japanese spirea reaches a modest height of 2 to 3 feet with a spread of 3 to 4 feet, making it incredibly versatile for smaller garden spaces or neat low hedges. It is remarkably adaptable, flourishing best in full sun but tolerating light shade. Its rugged nature means Spiraea japonica ‘Anthony Waterer’ is an excellent choice for gardeners seeking established color without demanding constant attention.

Beyond its visual appeal, the bright flower clusters of the Japanese spirea attract butterflies, adding beneficial movement to the landscape. Its ability to handle diverse soil conditions and urban stresses, such as air pollution, confirms its status as a reliable workhorse shrub in modern landscaping. Planting Spiraea japonica ‘Anthony Waterer’ guarantees consistent color and reliable form with minimal effort.

Fast Facts

• Plant Family: Rosaceae
• Plant Type: Deciduous shrub
• Hardiness Zones: USDA Zones 4-8
• Size at Maturity:
  • Height: 2-3 ft
  • Spread: 3-4 ft
• Bloom Time: May to August
• Bloom Description: Carmine red
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

The best time to establish your Spiraea japonica ‘Anthony Waterer’ is during the spring or early fall. Ensure it is planted in a location receiving full sun for the most intense flower production, though it will tolerate light shade. This shrub adapts well to many soil types; however, it thrives in average, well-drained soils with medium moisture content, preferring rich, moist loams for optimal vigor.

Care for this Japanese spirea is straightforward. Provide supplemental watering if the site experiences extended dry periods, as it prefers medium moisture. Fertilization is rarely necessary if the soil is reasonably fertile. Deadheading spent flower clusters, or at least light shearing after the initial bloom, encourages the secondary bloom period, extending the carmine red display well into late summer.

Pruning should be done judiciously, preferably in late winter or early spring before new growth starts, as Spiraea japonica ‘Anthony Waterer’ flowers on new wood. Heavy shaping should be avoided. Be aware that this cultivar can sometimes spread by suckering and may aggressively self-seed in certain environments, so monitor its growth habit, especially near natural areas.

Landscape Uses

The compact size and dense habit of Spiraea japonica ‘Anthony Waterer’ make it an excellent component for low, formal hedges bordering pathways and walkways where a neat, colorful edge is desired. It excels when massed or grouped within shrub borders, providing a strong block of color that contrasts nicely with finer-textured evergreens or broadleaf shrubs.

This Japanese spirea is also highly effective when used as an accent in rock gardens or integrated into foundation plantings, offering seasonal color close to the home. Consider pairing the carmine red blooms with silver-leaved plants or deep blue/purple flowering perennials that bloom concurrently or slightly later to accentuate its vibrant hue.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Spiraea japonica, commonly called Japanese spirea, is a dense, upright, mounded, deciduous shrub that typically grows 4-6’ tall with a slightly larger spread. The cultivar ‘Anthony Waterer’ is more compact, growing to 2-3’ tall and to 3-4’ wide, featuring carmine red flowers in flattened corymbs (to 6” wide) that appear in a showy bloom from late spring to mid-summer. Foliage offers seasonal interest, emerging with a reddish purple tint before maturing to blue-green and developing a reddish tone in the autumn.

Tolerances

• Deer
• Erosion
• Clay Soil
• Air Pollution

Potential Problems

Spiraea japonica ‘Anthony Waterer’ has no known serious, persistent insect or disease issues, contributing to its low-maintenance reputation. However, as a member of the rose family, it can occasionally be susceptible to issues affecting peers, including leaf spot, fire blight, and powdery mildew. Thankfully, this specific cultivar reportedly displays good resistance to powdery mildew. If fungal issues occur, ensure good air circulation during planting and apply preventative fungicide treatments if necessary during humid periods. Watch for common pests like aphids or scale, treating small infestations with insecticidal soap.

Frequently Asked Questions

What hardiness zones is Japanese spirea suitable for?

Spiraea japonica ‘Anthony Waterer’ is reliably hardy across USDA Zones 4 through 8.

How large does Japanese spirea grow?

This compact cultivar typically matures to a height between 2 and 3 feet, spreading 3 to 4 feet wide.

What sun exposure does Spiraea japonica ‘Anthony Waterer’ need?

For the best performance and most continuous bloom, Spiraea japonica ‘Anthony Waterer’ requires full sun exposure.

When does Japanese spirea bloom?

This variety features a significant bloom period running from May through August, showcasing carmine red flowers.

Conclusion

The Spiraea japonica ‘Anthony Waterer’ remains an outstanding selection for reliable structure and vibrant summer color in the landscape. Its low maintenance needs, coupled with excellent adaptability to varied soil types, make this Japanese spirea a gardener favorite. Before planting, confirm that your site falls within USDA Zones 4-8 and ensure it receives adequate sunlight to support its spectacular carmine red flowering display.

Companion Planting

Selecting companions that share similar requirements for sun and water will ensure a cohesive planting scheme. Plants that thrive in well-drained, medium-moisture soil and full sun will complement the Japanese spirea. Consider pairing the mid-summer color of Spiraea japonica ‘Anthony Waterer’ with perennials that offer late-season interest, such as Asters or Sedum, to provide continuous visual appeal from spring through fall. Mixing textures is also effective; fine-textured ornamental grasses or lacy native perennials create a pleasing contrast against the shrub’s dense foliage.

Design Ideas for Hedges and Borders

Due to its defined, mounded shape, this shrub is perfectly suited for creating formal or semi-formal hedges along property lines or walkways. For a colorful, layered border, plant Spiraea japonica ‘Anthony Waterer’ in the middle layer, backing it with taller, darker green shrubs like Arborvitae or Blue Holly for shadow and contrast. In the front foreground, use low-growing groundcovers or edging plants whose foliage color contrasts with the vibrant red blooms, such as Lamb’s Ears or creeping thyme.