Astilbes are easy-to-grown and maintain shrubs with amazing blooms that look great in any garden, landscaping, or container.
Astilbes are evergreen shrubs that are native to Japan, Korea, and China where they grow wild in woodland areas with moist soil.
There is only one variety of astilbes that is native to North America which is known as false goatsbeard.
They have elegant spike-like blooms that appear in late spring and last all season long.
Astilbes are a great addition to any garden or landscaping design with their large cluster of blooms with bold colors.
Because they prefer shade, they also make a great plant for underplanting trees.
PLANTING ASTILBE
Astilbes are best planted in hardiness zones 4 through 9 and have a soil pH range between 5.5 through 7.0.
They are best planted 18 to 24 inches apart in moist soil.
When planting an astilbe, it is best to make the width of the hole twice the width of the root ball.
Before filling in the hole mix some compost with the soil then fill in the hole.
This will add nutrients to the soil and help with water retention.
ASTILBE USES
Astilbes can help to brighten up any shady area with their spike-like feathery blooms. Because they prefer shade, they do well when underpainting trees.
They can also be used in raised garden beds and in large potting containers.
In cooler climates, they can be planted in partial sun with morning sun. In warmer climates, they should be planted in full shade.
FERTILIZING AND WATERING
Astilbes are best fertilized with granular fertilizer every spring or a homemade liquid fertilizer.
They require phosphorus for blooming therefore a 5-10-5 or a 10-10-10 mixture of nitrogen, phosphorus, and potassium is needed with the middle representing phosphorus.
When applying fertilizer, it is best to apply it between the base of the plant to the tips of the branches. This area of the plant is known as the drip line.
Astilbes require weekly watering but during the hottest days of summer, they will require more water.
They prefer the soil to be moist but be careful because over-watering can lead to issues such as root rot and powdery mildew just to name a few.
MULCHING
Mulching astilbes will help the soil retain water which will reduce the amount of time it takes to water them.
The thickness of the mulch is best between 1 and 2 inches deep for optimal water retention and the mulch will also help to prevent weeds from growing around your astilbes.
It is best to add new mulch every year as the older mulch breaks down.
BLOOMS
Astilbes have a cluster of blooms that have hundreds of tiny densely packed flowers that open in succession but they don’t bloom all at the same time.
Instead, the blooms open in a range from late spring to late summer with red, reddish-purple, pink, and white blooms.
Their blooms attract bees, butterflies, moths, and hummingbirds.
When their blooms become wilted you can remove them which will cause the plant to rebloom.
This is called deadheading and when the blooms are not able to go to seed, the plant will rebloom to produce seeds.
HOW TO PRUNE ATILBE?
Astilbe blooms will dry out but stay attractive with a different look and they can be left until the following early spring before being removed.
In the spring, if there is any dead or damaged growth then it should be removed.
Any stems that have wildly grown much higher than the rest of the plant which is known as leggy growth should also be removed.
If any of the dried blooms start to look ragged then they should be removed or they can be removed when they dry out.
PROPAGATING
Astilbe seeds take 20 to 25 days to germinate and can be started indoors 3 to 4 weeks before the last frost or sown in a garden or landscaping in early spring.
Every 3 to 4 years they will need to be divided, this is done by first carefully digging the plant up and using a spade or small shovel.
Gently separate the root ball into two sections, this is done to keep the size of the plant under control so it doesn’t take over the area it is growing in.
If you decide to divide them in the spring, make sure to do this in the early spring when the plant is still in its dormant stage.
During the fall they can go into the ground or container and plant the next spring.
PESTS
Astilbes have a few pests but they typically don’t cause much damage and there is no worry of them dying due to a pest infestation.
With that said they can stunt the growth of plants, and they may also introduce and spread any plant virus that they are carrying, therefore, eliminating them is a must.
- Black vine weevil
- Asiatic beetle
DISEASES
Astilbes that are planted close together can develop mold and mildew issues during times of high humidity.
If this is the case then preventive measures may need to be taken.
To prevent this from happening make sure to plant them far enough apart to allow for proper airflow.
OVERWINTERING
Astilbes like water and even though they are dormant, watering should continue until the first frost it is best to add about two inches of mulch after the first hard frost.
VARIETIES
There are several varieties of astilbe with a wide range of bloom colors, sizes, and foliage to choose from.
BRIDAL VEIL ASTILBE
- Plant size – grows to about 28 inches tall and 24 inches wide
- Drought tolerant – no
- Blooming colors – white clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
- Also known as – brautschleier astilbe
FANAL ASTILBE
- Plant size – grows to about 30 inches tall and 12 inches wide
- Drought tolerant – no
- Blooming colors – deep red clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
RHEINLAND ASTILBE
- Plant size – grows to about 30 inches tall and 30 inches wide
- Drought tolerant – no
- Blooming colors – pink to rose pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
FALSE GOATSBEARD ASTILBE
False goatsbeard astilbe is the only species that is native to North America where it grows in the mountains in the state of North Carolina.
- Plant size – grows to about 6 feet tall
- Drought tolerant – no
- Blooming colors – white clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
CHOCOLATE SHOGUN ASTILBE
- Plant size – grows to about 40 inches tall and 24 inches wide
- Drought tolerant – no
- Blooming colors – pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
HENNIE GRAAFLAND ASTILBE
- Plant size – grows to about 1 and a half feet tall and 2 feet wide
- Drought tolerant – no
- Blooming colors – pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
DELFT LACE ASTILBE
- Plant size – grows to about 3 feet tall and 3 feet wide
- Drought tolerant – no
- Blooming colors – dark pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
PEACH BLOSSOM ASTILBE
- Plant size – grows to about 2 feet tall and 2 feet
- Drought tolerant – no
- Blooming colors – peach clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
PUMILA ASTILBE
- Plant size – grows to about 12 feet tall and 12 feet
- Drought tolerant – no
- Blooming colors – reddish pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
SPRITE ASTILBE
Sprite astilbe is a dwarf hybrid variety that is great in potting containers or as a border.
- Plant size – grows to about 1 and a half feet tall and 1 and a half feet wide
- Drought tolerant – no
- Blooming colors – light pink clusters of blooms that form on a stem
- Foliage – glossy green oval foliage with jagged edges that forms a point at the tip of the leaf
- Deer resistant – yes
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