Astilbe
( ah - STILL - bee )
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At-A-Glance InformationPerfect for perennial borders, these plants are commonly called False Spirea or False Goat's Beard and need regular water and full sun exposure in cooler climates to perform well. Flowers are light and airy and will bloom from late spring through summertime. Blooms are small and can be pink, white, or red, carried in feather-like clusters at branch tips. Most species reach between 6 inches and 3 feet tall and 2-3 feet wide. The flowers will attract butterflies to your garden.
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AStilbe Species and Varietals
Astilbe is a member of the plant family Saxifragaceae, and includes around 15 species and many cultivars. False Spirea grows best in USDA hardiness zones 3-9 or Sunset growing zones A2, A3, 1-7 and 14-17, and can grow but is short-lived in Sunset zones 8, 9, and 18-24. To find your zone, click here: Zone Map.
Astilbe x arendsii (Astilbe Arendsii Group, False Spirea, Hybrid Astilbe)
This hybrid group was created mainly by growers and breeders in Holland and Germany, and include crosses between Astilbe astilboides, Astilbe chinensis, Astilbe japonica, and Astilbe thunbergii, among others. Flowers range in color from white to purplish-red. The cultivar group name arendsii is derived from the name of German horticulturalist Georg Arends. Most Astilbe plants sold commercially are of this species; varieties are outlined below.
This hybrid group was created mainly by growers and breeders in Holland and Germany, and include crosses between Astilbe astilboides, Astilbe chinensis, Astilbe japonica, and Astilbe thunbergii, among others. Flowers range in color from white to purplish-red. The cultivar group name arendsii is derived from the name of German horticulturalist Georg Arends. Most Astilbe plants sold commercially are of this species; varieties are outlined below.
'Amethyst'
A late-blooming variety with lavender flowers, grows to 3-4 feet tall. |
'Bridal Veil'
Blooms midseason to late in the season. Has full-white blooms on stalks 3 feet tall. |
'Color Flash Series'
Midseason blooms in pink with colorful foliage. 'Color Flash' is a great variety. |
'Deutschland'
Early blooming variety with white flowers on 1.5 foot stems and bright green leaves. |
'Fanal'
Early bloomer with blood red flowers and bronze foliage. Gets 1.5 to 2.5 feet tall. |
'Ostrich Plume'
Midseason to late season bloomer, with drooping pink clusters of flowers. 3-3.5 feet tall. |
'Peach Blossom'
Light salmon-pink flowers bloom in mid-season, grows to 2 feet tall. |
'Rheinland'
Early bloomer with deep pink flowers that gets 2-2.5 feet tall. |
Astilbe chinensis (False Goat's Beard, Tall False-Buck's-Beard, Chinese Astilbe)
These perennial herbaceous plants grow naturally along streams in moist soil, though they can tolerate dry soil. It is a commonly cultivated species used in shade gardens, and generally blooms in late summertime, producing shows of white to pink flowers. Use Astilbe chinensis to fill in woodland gardens, in cottage-style gardens, or as a groundcover (dwarf varieties are best for this purpose). Varieties are outlined and described below.
These perennial herbaceous plants grow naturally along streams in moist soil, though they can tolerate dry soil. It is a commonly cultivated species used in shade gardens, and generally blooms in late summertime, producing shows of white to pink flowers. Use Astilbe chinensis to fill in woodland gardens, in cottage-style gardens, or as a groundcover (dwarf varieties are best for this purpose). Varieties are outlined and described below.
'Diamonds and Pearls'
Pure white flowers bloom atop stems that are 2-2.5 feet tall. |
'Finale'
Pink flowers on stems 18-20 inches tall. |
'Purple Candles'
Light purple blooms on stems 3.5 feet tall. |
'Visions'
Early bloomer with an upright habit to 15 inches tall, raspberry-pink blooms and leaves are bronze-green. |
Astilbe chinensis davidii
Dense, pink blooms flower on stems up to three feet tall. |
Astilbe chinensis pumila
Low mats of leaves produce lilac-pink to mauve flower clusters up to 12-15 inches tall. |
Astilbe chinensis taqueti 'Superba'
This variety of Astilbe has rose-mauve flowers and grows to reach 4-5 feet tall at maturity. |
Astilbe chinensis taqueti 'Purpurlanze'
With reddish-purple blooms. |
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Astilbe glaberrima (Florist's Spiraea, Smooth Rock Astilbe, Yakushima Astilbe) This species reaches 4-6 inches tall and has a spread of 12-18 inches wide. These plants are fantastic in rock gardens due to their small stature. There are two subspecies, Astilbe glaberrima glaberrima, and Astilbe glaberrima saxatalis. |
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Astilbe japonica (False Buck's Beard, Florist's Spiraea, False Goat's Beard, False Astilbe, Japanese Astilbe) This species is native to Japan, and reaches up to 1.5-3 feet tall at maturity when in bloom. Commonly grown cultivars include 'Deutschland' (with white flowers), 'Montgomery' (dark magenta blooms), and 'Rheinland' (with clear pink flower panicles). |
Astilbe simplicifolia (Entire Leaved Astilbe, Entire Leaved False Goat's Beard)
This species is native to Japan and North Korea, and reaches 1.5 feet tall and wide; leaves are not as divided as most others are in the genus Astilbe. The specific epithet simplicifolia refers to the fact that these plants have simple leaves. This species has many varietals and hybrids made for gardens, some of which are outlined below:
This species is native to Japan and North Korea, and reaches 1.5 feet tall and wide; leaves are not as divided as most others are in the genus Astilbe. The specific epithet simplicifolia refers to the fact that these plants have simple leaves. This species has many varietals and hybrids made for gardens, some of which are outlined below:
'Pink Lightning'
Delicate blooms emerge purple-red and open up to reveal clear pink flowers. |
'Sprite'
Low-growing, compact plant that blooms profusely in summer with pink flowers and bronze leaves. |
'Hennie Graafland'
Similar to 'Sprite' but grows a bit taller and blooms earlier in the season. |
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Astilbe thunbergii (Astilbe Ostrich Plume, Thunberg's Astilbe, Strussenfeder) This species is native to Japan, and has a very notable cultivar, 'Straussenfeder' (pictured). Plants form clumps of foliage and arching sprays of bright flowers in summertime. They can reach up to 30 inches tall and almost as wide. Great for fresh-cut flower bouquets. |
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Caring for Astilbe
Astilbe plants can be grown from seed or purchased as specimens from a reputable nursery. The best time to plant these flowers in in the shoulder seasons (spring or fall). Plant these flowers in a spot in the garden that receives partial shade; the ideal sun exposure is around 4 hours each day. They can also receive filtered sun all day, though they will bloom more frequently the more direct sun they can get. Astilbes need well-draining moist (but not wet) rich soil with ample humus. If local soils are compacted, do not drain well, or are particularly poor in nutrients, make sure to amend the planting area with plenty of organic matter or compost before installing. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants perform well in consistently moist soils. Apply a thick layer of mulch around the base of plants, ensuring that mulch stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature.
Faded flower stems should be dead-headed; though this will not encourage more blooms to form, it does help to keep plants looking tidy and prevents re-seeding. Clumps of flowers should be divided every 3-4 years to keep a neat appearance and for the ongoing health of these flowers. For instructions on how to divide plants, see the Propagation section below. Fertilize Astilbe plants yearly in early springtime using organic compost, pulling back mulch before applying. Work the compost into the soil, water, and then replace mulch around the base of the plant. These plants do not need any additional fertilizing. False Goat's Beard is a long-lived perennial plant that can last for 10 years or more in the garden.
Harvesting Astilbe
Astilbe make beautiful additions to cut flower arrangement, adding height, color, and structure. They are typically available for harvesting in late spring through late summertime. Species commonly grown for their cut flowers include Astilbe chinensis, Astilbe arendsii, Astilbe thunbergii and Astilbe x arendsii. Astilbe flowers are harvested when the inflorescence is halfway open, with the top buds still swollen with dark color. The best time of day to harvest flowers is in the morning after dew has dried but before the heat of the day sets in. Using sharp, sanitized shears, cut the flowering stem at its base at an angle, and drop the stem into a bucket of cool water. When arranging, remove all leaves below the water line and replace water every few days. Stem bases can be snipped to extend vase life, which is typically between 7 and 14 days.
Faded flower stems should be dead-headed; though this will not encourage more blooms to form, it does help to keep plants looking tidy and prevents re-seeding. Clumps of flowers should be divided every 3-4 years to keep a neat appearance and for the ongoing health of these flowers. For instructions on how to divide plants, see the Propagation section below. Fertilize Astilbe plants yearly in early springtime using organic compost, pulling back mulch before applying. Work the compost into the soil, water, and then replace mulch around the base of the plant. These plants do not need any additional fertilizing. False Goat's Beard is a long-lived perennial plant that can last for 10 years or more in the garden.
Harvesting Astilbe
Astilbe make beautiful additions to cut flower arrangement, adding height, color, and structure. They are typically available for harvesting in late spring through late summertime. Species commonly grown for their cut flowers include Astilbe chinensis, Astilbe arendsii, Astilbe thunbergii and Astilbe x arendsii. Astilbe flowers are harvested when the inflorescence is halfway open, with the top buds still swollen with dark color. The best time of day to harvest flowers is in the morning after dew has dried but before the heat of the day sets in. Using sharp, sanitized shears, cut the flowering stem at its base at an angle, and drop the stem into a bucket of cool water. When arranging, remove all leaves below the water line and replace water every few days. Stem bases can be snipped to extend vase life, which is typically between 7 and 14 days.
Propagation
The best ways to propagate these plants is via seed or division. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are harvesting seed from a hybrid cultivar. To propagate your Astilbe plant, follow the instructions below:
Propagating Astilbe by Seed
Propagating Astilbe by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring, and needs to be done every 3-4 years. To propagate Astilbe by division, follow these steps:
Propagating Astilbe by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
- Harvest your seeds. The seeds of Astilbe plants are contained inside of the dried flowering heads of plants, which will turn brown and dry when mature. Once they have dried out completely, cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to release the seeds, and this process can be helped along with some rough handing (shaking of the bag). Once seeds have been released, take them out of the bag and put them in a container so you can work with them.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes about 28 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Propagating Astilbe by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring, and needs to be done every 3-4 years. To propagate Astilbe by division, follow these steps:
- Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the rhizome roots. Once you have worked it up out of the ground, lay it out.
- Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section with between 3 and 5 eyes.
- Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided rhizomes about an inch under the soil surface and water thoroughly.
- Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout over the spring and summer seasons.
Astilbe seeds are held inside of the seed heads produced by plants in fall.
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Astilbe seeds are very small.
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Problems and Pests
Astilbe plants can suffer from issues with the following landscape pests and diseases:
- Powdery Mildew
- Leaf Spot
- Aphids
- Whitefly
- Japanese Beetle
- Black Vine Weevil
Gallery
Astilbe flowers are very popular garden ornamentals thanks to their bright spikes of small blooms.
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Astilbe is a natural companion to other shade-loving plants like ferns and Hostas.
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Astilbe's white flowers contrast nicely against the broadleaf evergreen background of this shady border.
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A pathway bordered on both sides with white-flowered Astilbe and purple Delphiniums.
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Videos
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How to grow Astilbe plants in the garden.
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Astilbe is featured in this springtime cleanup video.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 177 - 178, Astilbe
