Easy-to-follow advice for successfully cultivating astilbe

Astilbes are truly majestic when topped by a profusion of white, pink, salmon, lilac or red feathery blossoms that linger for weeks in summer. However, don't be fooled by their delicate-looking flowers or fern-like foliage. These splendid perennials are extremely cold-hardy and quite easy to grow. Here's some advice to help you.

[Image credit: iStock.com/Pascal-L-Marius]

The beauty of astilbes is they're quite forgiving when it comes to the sun.

• Astilbes are not strictly for shade, although they are often grown there. Where summers are not oppressively hot you can grow this plant in full sun and it will thrive.
• Because astilbes are shade-tolerant, they're ideal for brightening patches under tall trees or walls and fences. A swath of astilbes can turn a damp, hard-to-plant area into a showpiece. In shady settings, plant astilbes with hostas.
• Given a little more sun, astilbes make pretty companions for bee balm, lady's mantle and irises.
• Astilbes also look gorgeous in containers with ornamental sweet potato vines, dahlias and liquorice plants. Since they're not fussy about getting too much or too little sunshine, they can be easily moved around especially if they're planted in containers.

Astilbes offer a broad range of flower colours with bloom times that vary. You can readily combine them for an extended period of colour in your garden.
Popular varieties include:

• 'Sprite' which is a charming pink-flowered miniature, perfect for edging or containers and hardy enough to overwinter in outdoor pots.
• The widely available Astilbe × arendsii cultivars bloom in June and July and range from deep-red-flowered 'Fanal' and dark pink 'Gloria Purpurea' to purple 'Hyacinth' and frothy white 'Bridal Veil'.
• A. chinensis cultivars, such as mauve-flowered 'Finale' and rose 'Serenade', usually bloom in August, as do the tall and stately 'Superba' and other A. tacquetii cultivars.
• Very late-blooming A. chinensis 'Purple Candles' begins in August and continues into September.

The optimal site for growing astilbe has consistently moist, fertile soil. To plant:

• First, lay down about six-and-a-half centimetres (two-and-a-half inches) of organic material where you intend to plant the astilbe.
• Next, dig a hole to comfortably seat the plants without crowding the roots.
• Finally, cover the soil around the plants with a five-centimetre (two-inch) layer of moisture-retaining compost or leaf mould.

To increase flowering in subsequent years, fertilize in spring with an organic or controlled-release fertilizer.

• After three to five years the plants may become crowded. To rejuvenate them, lift the plants and use a knife or sharp shovel to divide the woody bases before replanting.

Astilbes wilt and brown quickly if not watered during drought.

• They can go dormant and may eventually perish. The first symptom of dissatisfaction is leaf tip browning, but new growth will sprout if supplemental water is forthcoming.
• When you water, soak the soil deeply, allowing it to dry between waterings.

Other than root rot, which occurs when the soil is constantly soggy, astilbes readily resist disease.

Although the plants are virtually pest-free, raggedly chewed leaves can reveal the work of night-feeding slugs and snails.

• Set saucers of flat beer on the soil to lure and drown these pests.
• In the eastern part of the country, Japanese beetles may chew leaves of plants growing in full sun. Spray with insecticidal soap.
• To avoid future problems with sun-loving beetles, plant astilbe in partial shade.

Astilbes are no-nonsense, trouble-free flowers that can survive for years. So whether you plant them in a bed or container, they’re sure to add a dramatic hue of colour and texture to your garden or backyard.