Plant guide: astilbes

With a huge frothy plume of flowers in the late summer, held above elegant fern-like foliage, Astilbes are an excellent plant for damp and shady conditions.

This tall-growing deciduous plant is perfect to make an eye-catching statement in a shaded spot towards the back of a border, or enjoying damp conditions in a rain garden.

Easy to grow (as long as they’re in damp soil) and with flower heads that stay in place throughout the winter months to provide structure, as well as habitat for wildlife, we love to include astilbes in our planting plans.

Botanical name: Astilbe spp.

Plant type: Hardy perennial

Growing conditions: Astilbes are usually a tallish plant, growing up to about a metre, so do well towards the back of a border. They need damp soil, and prefer part shade, so tend to grow well in boggy gardens, in rain gardens or at the edge of water.

They prefer a rich soil, so grow best in areas of high fertility. If you have poor soil, then digging through plenty of well-rotted organic matter before planting can help them establish, but you will need to top up with plenty of mulch in subsequent years. They also grow well in pots – especially if you choose a smaller variety – so this can be a great way to provide them with the perfect compost.

Tiny delicate flowers held in spikes create a firework of froth above the leaves!

Astilbe foliage is elegant and eye-catching, with delicate dissected leaves

How to plant:

There is a huge range of astilbes available to buy, with varying sizes and flower colours of white, pinks and reds. They’re easy to find in plant nurseries and garden centres, and usually are available as container grown plants in one or two litre pots.

It’s best to plant them out in Spring or Autumn (planting in Autumn will mean they won’t need so much watering over the wet Winter months, and their roots will establish well before flowering the following year.)

To plant out, dig a hole to the depth of the pot and twice as wide. Gently squeeze the edges of the pot to release the plant, and put it into the hole. Back fill and firm in. Water well.

For more on planting, see our guide How to plant out container grown plants.

Care:

Though generally low-maintenance, astilbes need plenty of moisture to grow well, so will need watering in any dry and hot spells in the Summer months.

Once the flowers are over, they can be dead-headed, or you can leave the flower spikes in place, where they will gradually turn bronzey brown, and provide wildlife habitats and structure in a winter garden. Leave in position in Spring, and cut back before new growth appears.

Astilbes can be divided every four years or so, to prevent overcrowding. Dig up a clump, taking care to dig deep enough so as to damage as few roots as possible. With a sharp spade, cut the clump in half, and replant one half in the original spot. The second half can be planted somewhere new…

Uses:

The striking flower heads of astilbes are really popular as a cut flower. Cut from the flower once all the buds on the flowering spike have opened. Condition overnight, and then arrange in a vase. Flowers will last one to two weeks once cut.

Grow with:

Astilbes are perfect for a shady garden spot, and grow well with other plants that fit the same conditions. Pair them with broad-leaved hostas or rodgersia for eye-catching contrast to their delicate leaves.

We often pair astilbes with ferns, especially Asplenium scolopendrium (Hart’s tongue fern) whose strap-like glossy leaves contrast well with the delicate astilbe foliage.

As they do well in damp conditions, they’re a popular plant to grow around a pond, or in damp places. We use them often in rain gardens.

Favourite varieties:

Astilbe ‘Fanal’ is a reliable astilbe that we use a lot, with vibrant pink flowers that make a real impact.
Astilbe ‘Vision in White’ is, as the name suggests, a beautiful white-flowered variety.
Astilbe ‘Dark Side of the Moon’ is a really unusual pink-purple flowered astilbe with deep purple leaves. We’ve yet to plant this one, but are excited to try it out soon…