Astilbe [a-STIL-bee] is a genus of approximately 25 species and hundreds of hybrids of herbaceous perennials belonging to the Saxifragaceae family.
These rhizomatous flowering plants are popular for their tall, feather-like colorful plumes which grow on slender vertical stalks over airy, fern-like foliage.
Some common astilbe varieties are:
Chinese astilbe (A. chinensis)- It produces brilliantly colored flowers late in spring and grows up to 2’ feet.
This is drought and heat resistant species.
Star astilbe (A. simplicifolia): It has thin stalks, shiny leaves, and tiny star-shaped white blossoms.
This variety grows no more than a foot in late spring.
Japanese astilbe (A. japonica): It is a small-sized hybrid with big flowers growing in dense pyramidal clusters during midsummer.
Hybrid astilbe (Astilbe × arendsii): Hybrid varieties are the most varied and most common species found in shade gardens.
They bloom early in summer.
Astilbe arendsii ‘Fanal’ (False Spirea): Blooms early with blood-red flowers on bronze foliage.
Astilbe arendsii ‘Rheinland’: Another early bloomer in rich pink and very hardy.
These part shade-loving plants are native to the mountains, ravines, and woodlands of North America and Eastern Asia.
Some common names of astilbe plants are:
- False goat’s beard
- False spirea
- Florist’s spirea
Astilbe Plant Care
Size & Growth
The growth habit in astilbe plants varies according to the species.
Some dwarf species are as small as 6” inches in height, whereas others can grow as high as 2’ feet.
The plant spreads from 6” inches to 5’ feet in width.
Flowering and Fragrance
Astilbe plants are evergreen perennials producing gorgeous dark green foliage and occasional bright chartreuse, bronze, burgundy, and chocolate foliage in early spring.
The attractive feathery, bottlebrush-shaped astilbe flowers grow in 6” inches to 2’ feet high cluster flower heads.
Flower colors include creamy white plumes, light pink flowers, lilac, deep purple, and bright red creating beautiful flower spikes.
These colorful plume-like flowers add seasonal color to the summer gardens.
Astilbe plant species are categorized in early spring, midseason, and late summer bloomers.
A combination of these species are grown to enjoy the blooming season ranging from May through September.
The bloom time lasts for 4 to 6 weeks for the flower plumes to reach maturity.
Light & Temperature
Astilbe plants prefer partial shade to full shade.
They can add color to the shady areas of the garden with part-sun and can even survive the full sun.
However, as the temperature rises in dry regions, full sun exposure can harm the foliage and make the leaves brown and dry.
These showy plant types can withstand extremely hot weather if provided with plenty of water and a shady spot.
They are hardy in USDA hardiness zones 3 through 8.
Watering and Feeding
During warm weather or full-sun exposure, astilbe plants need plenty of moisture.
These plants are not drought-tolerant for prolonged time periods.
These plants need phosphorus-rich fertilizers to bloom.
A fertilizer with 5-10-5 or 10-10-10 combination should be added to the soil with a rake at least 2 weeks before planting.
Sprinkling the granules of the organic matter over the soil is also beneficial.
Once the plant has held its ground, add fertilizer to the moist soil every spring.
Soil & Transplanting
Astilbe plants grow best in soil rich, organic, and moist.
The soil must be well-drained and slightly acidic with a pH around 6.0.
If you have clay-type soil in your garden, add peat moss, perlite, other organic material, and coarse sand to improve drainage and moderate moisture.
In the case of poor, lean, or rocky soil, add compost for enrichment.
The crown of the astilbe plant must align with the soil level when planted.
Cover the crowns protruding out of the soil with humusy soil or use the clumps for transplanting.
Grooming and Maintenance
Although astilbe plants need very little maintenance, they must be watered well on a regular basis throughout the growth period, especially plants growing under direct sunlight.
An optimum combination of shade, water, and fertilizer is essential as it keeps the leaves from drying or burning and results in bigger blooms.
The dried flowers add to the beauty of the plant for months before they’ll need pruning.
Cut back the ragged or spent flowers during the spring season.
In winter, when the plant has sustained first hard frost, add 2” inches of mulch to the soil surrounding the stem.
This will help maintain the soil temperature.
How to Propagate False Goat’s Beard
Astilbe plants are propagated by division.
- These clumping perennials spread quickly and should be divided every four to five years.
- In ideal conditions the rate of growth and spread may increase, needing frequent division.
- Divide the overgrown clumps and replant them.
The clumps are also stored in containers and allowed to establish themselves before planting them in early summer.
If you plant astilbe seeds to grow these plants just know they’re difficult to germinate and have a limited life, it isn’t the most preferred method.
- Plant the divisions about 1’ to 3’ feet apart.
- Plants with bare roots are buried 4” to 6” deep with roots pointing downwards.
- The crown should be pressed 1” to 2” below the ground level and covered with rich soil for support.
Keep the astilbe plants away from direct sunlight, as this will interfere with their ability to produce long-lasting foliage and flowers.
False Goat’s Beard Pest or Disease Problems
Astilbes are usually free from pests and disease problems.
However, during their growing phase, groundhogs and rabbits may snack on the young leaves and soft stalks.
All varieties such as Astilbes ‘pumila’ are deer-resistant.
These plants are occasionally infested with tarnished plant bugs.
Some rare diseases include a fungal disease called powdery mildew and leaf spots caused by bacteria.
Suggested Astilbe Plant Uses
Astilbe plants like the bridal veil are shade-loving perennials ideally grown in brightly lit woodland gardens and shaded gardens with other popular perennials like heuchera, hosta, and yellow rocket.
The large feathery plumes and fern-like foliage of this hardy plant are used to accentuate the pond-side areas.
A number of hybrid cultivars are planted under maples and oaks and near streams to create a gorgeous landscape with fresh colors and pleasant fragrances.
Astilbe chinensis also makes a good groundcover.