How to Propagate Astilbe Flowers Through Division

Allow me to introduce you to the magic of the perennial, shade loving, Astilbe. One single plant can turn your backyard (if it’s shady enough!) into a charming oasis bathed in lavish plumes and lacy foliage.

We’re going to talk about how you can take that one parent plant you bought at the nursery and transform it into as many baby plants as your heart desires.

Astilbe plants vary in size and color. There are some plants that will not top six inches while others may finish their season at a whopping four feet tall – buyer beware!

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Make sure to pay attention to which varieties you purchase at the nursery, lest you unknowingly plant a variety that may form a veritable forest.

If you are propagating from a plant that you’re already familiar with from your backyard, you can expect a similar height from the propagated (or “baby”) plant as displayed by the parent plant.

Colors vary from white to dark shades of purple and pink. Their foliage also varies from greenish bronze to dark green, depending on the cultivar and the soil’s available nutrients.

Propagation

Astilbe can be successfully divided in fall or early spring.

If divided in fall, you can directly replant the new divisions, or you can store them in pots in your garage for the winter to gift to your friends, or for planting in your garden the following spring. Wait to divide the rhizomes until after the plants have finished flowering.

If you choose to divide them in the springtime, do it early during their dormant stage so that once they start growing, they have a full season to establish themselves.

Another important note before planting: make sure to observe where the sunshine and shade fall in your garden during the spring and summer months. Once autumn and winter roll around, the light patterns will change. Astilbe grows best in partial shade in the warmer seasons, but it can tolerate full sun.

Now that you’ve decided on the optimal location for your freshly divided Astilbe, let’s talk division and multiplication!

Ideally, to keep your parent plants healthy, you’ll want to divide them about every four years.

Additional Notes for Division in the Fall

If it is autumn and you want to store your divisions instead of directly replanting the rhizomes into your garden beds, you can plant each new transplant in well-draining potting soil in a medium-sized pot. Place it in your garage or cellar, in a dark and cool location, and wait until spring to decide what you want to do with them.

You don’t want to water the pots much during the winter while they are dormant, but try not to let them get so dry that the roots shrivel. A cup of water every two to three weeks should be just fine!

Remember that if you choose this route, you’ll need to follow steps 2-4 and 7-9 as described above the following spring, when the ground has begun to warm up and you are ready to plant. Any rhizomes showing signs of mold, rot, or decay should be discarded.

The last element of the process, if you choose to embark on it in the fall, is a great big dose of patience. Your newly transplanted Astilbe are not likely to bloom in their first growing season. However, you can expect to see blooms starting in year 2 and onward!

The fireworks of Astilbe plumes will be well worth the wait, I assure you.

Some Final Thoughts While You Wait…

There are few greater joys than beautifying our gardens. Taking some extra time to divide and thereby multiply the Astilbe in your garden beds is worth it. The parent plant will be healthier with more room to spread, and the number of blooms in your beds will be more numerous.

Remember the key principles that will keep your plants happy: rich, well-drained soil; regular deep watering without constant wet feet; 2-3 hours of sun per day; and annual fertilizing with a mix that is high in phosphorus and potassium.