Some varieties of Astilbe are also known as ‘False goat’s beard’ – for example Astilbe Fanal x arendsii, which has serrated, dark green foliage and deep red-coloured flowers. This fluffy rhizomatous plant will not only add colour to your garden, but also depth and texture, as a result of the unusually shaped plumes.
As a hardy plant, Astilbe grows well in a UK climate and can be an ideal choice for areas where less tolerant plants might struggle, such as shaded locations or waterlogged soils. The fern-like appearance of the plumes looks particularly great in garden borders, alongside grasses and ferns.
If you’re considering adding Astilbe to your plant collection, read on for our full care and growing guide, and discover the truth about what it takes to grow False goat’s beard in a UK garden.
Background, Origins & Varieties
Astilbe originates from parts of North America and Asia, and is a member of the Saxifragaceae family. There are at least 18 different varieties of Astilbe, and many more hybrids. Each variety has a different height, flowering time and flower colour. Colours vary from white and pink, to red and lavender.
Some varieties are commonly referred to as ‘False goat’s beard’, including Astilbe ‘Fanal’ (x arendsii), which produces deep red flowers in early summer, and Astilbe chinensis (Chinese astilbe), which originates from China and Japan, and has pale pink flowers.
As well as False goat’s beard, other names for Astilbe include Meadowsweet and False Spiraea. These names come about because the feathery clusters of Astilbe give it a similar appearance to the true Goat’s-beard (Aruncus dioicus), and Spiraea plants.
Astilbe is a popular choice for shaded gardens, and works well with other shade-tolerant plants, such as rodgersias and hostas, as well as grasses and ferns. It is often planted as part of a border, with several varieties of differing heights, and will add long-lasting colour and texture to your garden.
Another common home for Astilbe is around a garden pond or stream, thanks to its fairly rare preference for waterlogged soil. Astilbe is a very low maintenance plant, with few common pests, and is therefore one of the easiest perennials you can add to your garden.
Feeding, Care & Growing Tips
Unlike many plants, Astilbe does not need full sunlight to produce its beautiful flowers – in fact, it favours the shade. It will, however, benefit from a little sun, to help it produce larger blooms. The best location to choose for it is one of partial or dappled shade, with perhaps an hour or two of sun throughout the day. To plant your Astilbe, dig a large hole, and add some well-rotted organic compost.
Astilbe can tolerate all types of soil – including acidic – with the exception of dry soil. As it needs a high moisture content, it will also do well in a boggy or waterlogged spot, where many other plants might struggle – for example by a stream or pond. Make sure to water your Astilbe regularly, and mulch the soil annually to help with water retention.
Astilbe is a hardy plant, and apart from watering, requires little ongoing care for it to flourish and flower each season. It will die back to ground level each autumn after flowering, and fresh growth will appear the following spring. You can add a slow-release, high-phosphorus fertiliser at this time, to aid the summer’s flowering.
Most varieties of Astilbe can tolerate freezing temperatures (some even down to -30°C), so there’s no need to bring your plant inside or cover it during winter. This is, however, a good time to apply your mulch, to help keep roots moist during frost.
Astilbe plants do not need to be pruned. If you decide you want to trim them back to keep them tidy, the best time to remove old growth is in late autumn after flowering, or in early spring when the new growth starts to appear.
Another reason you may want to cut the dead stems back is to make it easier to add a mulch to the soil during winter. In this case, cut the stems back to 5-10cm above ground level, and you will find the base of the plant much more accessible.
When To Plant Astilbe
Although you can plant Astilbe from seed, this is not the easiest choice, as it can be hard to germinate. Most people tend to purchase bare-rooted Astilbe plants when they are readily available in early spring, or acquire them by division.
The best time to plant a new, bare-rooted Astilbe is in early spring, immediately after purchasing. Make sure to keep your Astilbe wrapped in a moist paper plant to prevent the roots from drying out, and get it in the ground as soon as possible.
When planting, try to choose a partially shaded location with moist, humus-rich soil. If the soil is of poor quality, add well-rotted manure or organic compost upon planting. Water liberally, especially if it’s dry, and mulch the soil, to encourage water retention.
If you’re planting Astilbes that have been propagated by division, it is best to plant them later in spring. Position them at least 0.5m apart, to ensure good air circulation between plants. See below for more information on how to propagate Astilbes.
Habitat & Growing Conditions
Astilbe’s natural habitat is the valleys, mountain ravines and woodlands of North America and Asia, where it often grows in shaded and boggy conditions. As a result of this, the plant does well in partial shade and favours moist or waterlogged soil. It does not like full sun or high temperatures.
Ideally, Astilbe prefers soil that’s loamy and humus-rich, although it will grow in pretty much all soil types and pHs. Just make sure the soil doesn’t dry out, as Astilbe will not tolerate this. This is especially important if it’s in a sunny location, in which case lots of watering will be required.
Astilbe plants are very easy to propagate – you can do this by dividing them once they have grown into a large clump. In order to keep Astilbe plants looking their best, and stop them from becoming congested, you should aim to divide them approximately every 3 years. The best times to propagate are in autumn or early spring.
To do this, you should lift the plant gently out of the ground using a fork, being careful not to damage the roots. Shake the soil from the roots, and gently pull the root mass apart into two smaller clumps. If the root ball is particularly dense, you may need to use a sharp implement to assist you.
Once the roots are separated, you can choose to plant your new plants back in the same spot, or pot them to build up their size, and then plant them out in late spring or early summer. Position propagated plants at least 0.5m apart, to ensure they have plenty of room to grow.
Common Diseases & Problems
Astilbe is generally not prone to disease. One possible concern is powdery mildew, particularly due to Astilbe’s love of damp, shaded growing locations. Powdery mildew is a fungal infection which can lead to a powdery white coating on your plant’s leaves and flowers, as well as distorted leaf growth.
To help avoid powdery mildew, make sure not to over-fertilise the soil, and don’t plant too densely, as this will stop air from circulating around your plant, encouraging the conditions for mould. Division of a dense plant can also help. If your plant shows signs of infection, you can tackle it by immediately pruning the affected areas, and removing any fallen infected material on the ground. You can also apply a fungicide.
Another disease that may affect Astilbe is Bacterial Leaf Spot. The most obvious symptom of this is black or brown spots on the leaves. Unfortunately, it is not possible to completely eradicate Bacterial Leaf Spot once your plant is infected, but it can be controlled with the use of a fungicide.
There are not many pests common to Astilbe plants. Occasionally, they might succumb to an infestation of tarnished plant bug – a 5mm, yellowy-brown bug, that feeds on plant tissue, sucking juices from leaves and shoots.
These bugs can be controlled using insecticides, or by applying a garlic spray to your plant, to discourage feeding. You should also remove weeds and dead leaves from the area around your plant, so the bugs have nothing else to feed on, and nowhere to hide over winter.
When you first plant your Astilbe, you may notice hedgehogs and rabbits nibbling on the leaves, but once the plant is established, it is generally fairly resistant to becoming wildlife fodder.
Frequently Asked Questions
How big do astilbe get?
Astilbe plants can grow to anywhere from 20 – 140cm in height, depending on the variety. It will usually take 2 – 5 years for the plant to grow to its maximum height. The flowering plumes range from 20 – 60cm, again depending on the variety.
Is astilbe deer resistant?
Although no plant is completely deer-proof, the good news is that Astilbe is rarely bothered by deer, as they tend not to be too keen on the fern-like plumes and fragrant scent of the flowers. However, bear in mind that fawns will often try anything whilst they’re young, as they’re still learning what’s good and what’s not.
Does astilbe like shade?
Astilbe is a hardy plant, native to sheltered woodlands and ravines, and therefore is very used to shade. It will grow best in a partially or almost fully shaded position in your garden. Ideally, the location will receive some sun, for perhaps 1 – 2 hours each day, to encourage blooming. The plant is hardy and can cope in full sun, but it will need to be watered plentifully, as it cannot tolerate dry soil.
Should you deadhead astilbe?
Astilbe plants do not need to be deadheaded. You can still deadhead if you want to, but just be aware that doing so will not encourage new flower growth. Many gardeners prefer to leave the dead seed heads, as the browning flowers will dry and continue to add texture, interest and an attractive look to the garden, well into the autumn months.
When should you cut back astilbe plants?
It is not essential to prune Astilbe plants. If you want to cut them back, the best time to do so is either in late autumn, after flowering, or in early spring, when you can remove the old growth to make way for the new. If cutting back in autumn, you can take them down to 5cm above ground level, to make way for mulching.
Can you grow astilbe in pots?
It is possible to grow Astilbe in pots, and they look very effective when grown as individual plants. It is advisable to choose a shorter variety for container growth. Make sure to use a high-quality potting compost, and water your plant regularly. Unlike with most container plants, drainage is not important, as Astilbes favour waterlogged soil.
One advantage of growing Astilbe in pots is that you can move them into a shadier area if they start to dry out. Their preference for shade also makes them a perfect choice for container plants on a sheltered deck or patio, or in a north-facing garden.
Why is my astilbe dying?
The most common reason for ill health in Astilbe plants is that the growing conditions are too hot and/or dry. If your Astilbe is in a sunny or partially sunny location, try moving it more into the shade. Increase the amount and frequency that you are watering the plant, and check the soil regularly to make sure it’s not drying out. Try adding mulch to encourage it to better retain water.