Astilbe Rubra

Description

Astilbe Rubra is a herbaceous perennial that belongs to the Saxifragaceae family. It is native to Asia and North America and is widely cultivated for its beautiful, long-lasting flowers. This plant is commonly known as False Spirea or False Goat’s Beard due to its plume-like flowers that resemble the spirea shrub and goat’s beard plant, respectively. Astilbe Rubra is an excellent choice for gardeners who want to add color and texture to their garden beds, borders, or containers.

Taxonomic Information

Appearance

Astilbe Rubra grows up to 2-3 feet tall and spreads up to 1-2 feet wide. Its dark green leaves are deeply lobed and fern-like, providing an excellent backdrop for its showy flowers. The flowers bloom in early to mid-summer and form dense, upright plumes that vary in color from deep pink to red. The plumes are composed of numerous tiny flowers and can reach up to 12-15 inches in height. The plant prefers moist soil and partial shade but can tolerate full sun in cooler climates.

Care Guide

Astilbe Rubra is a low-maintenance plant that requires minimal care. Here are some tips to keep it healthy and thriving:

• Water: The plant prefers moist soil, so water it regularly to keep the soil evenly moist. Avoid overwatering, as this can lead to root rot.
• Fertilization: Apply a balanced fertilizer in early spring to encourage healthy growth and blooming.
• Soil: Astilbe Rubra prefers rich, humusy soil that is moist but well-draining. Amend the soil with compost or peat moss to improve its texture and fertility.
• Sunlight: The plant prefers partial shade but can tolerate full sun in cooler climates. In hot, dry climates, it is best to provide afternoon shade to prevent the plant from drying out.
• Hardiness Zones: Astilbe Rubra is hardy to USDA Zones 4-9, making it suitable for most regions of the US.

Common Pests & Diseases

Astilbe Rubra is generally free of pests and diseases. However, it can be susceptible to powdery mildew, a fungal disease that appears as a white, powdery coating on the leaves. To prevent powdery mildew, avoid overhead watering and provide good air circulation around the plant. If necessary, treat the plant with a fungicide spray.

Habitat

Astilbe Rubra is native to Asia and North America, where it grows in moist, woodland areas and along streams and rivers. It is commonly found in shaded areas with rich, humusy soil. The plant is well-adapted to these habitats and can thrive in similar conditions in the garden.

Question and Answer

Q: How often should I fertilize Astilbe Rubra?
A: Apply a balanced fertilizer in early spring before the plant begins to grow. Repeat the application every 4-6 weeks during the growing season.

Q: Can I grow Astilbe Rubra in a container?
A: Yes, Astilbe Rubra can be grown in a container as long as it has good drainage and is kept evenly moist. Use a high-quality potting mix and fertilize regularly to encourage healthy growth and blooming.

Q: Can I divide Astilbe Rubra?
A: Yes, Astilbe Rubra can be divided in early spring or fall when it is not actively growing. Dig up the clump and separate it into smaller pieces, making sure each piece has several healthy roots and shoots. Replant the divisions in a well-prepared bed or container.

Q: How do I propagate Astilbe Rubra?
A: Astilbe Rubra can be propagated by division, seed, or stem cuttings. Division is the easiest and most reliable method, while seed and cuttings require more skill and patience.

Related Plants

• Astilbe Chinensis
• Astilbe Japonica
• Astilbe Arendsii
• Astilbe X Thunbergii

References

• “Astilbe Rubra.” Missouri Botanical Garden. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c630
• “Astilbe Rubra.” The Spruce. https://www.thespruce.com/astilbe-rubra-growing-profile-4847179
• “Astilbe.” Garden Design. https://www.gardendesign.com/plants/astilbe.html