Albizia are gorgeous creatures, rarely seen but prized when they are for their showy flowers of many stamens. All of them have lovely bipinnate foliage, so distinctive to the legume family, but some are an attractive chocolatey brown rather than green.
There are around 150 species, found in tropical regions of Africa, Asia and South America. They are deciduous shrubs, small trees and climbers that have compound foliage reminiscent of the mimosa. The trees tend to create a shape like an open umbrella.
Because they hail from the tropics they are not hardy trees, and some claim they should not be risked in the UK. But it would be a shame not to risk it — you would miss their stunning pink, powder-puff flowers, which are produced in summer.
They can do well in mild parts of the UK, such as hotspots in London or the South West. They should be planted in warm, sheltered sites on well-drained soil and even cope with impoverished soils.
The only species grown in any number in the UK is A. julibrissin, also known as the "silk tree". It comes from the region between China and Iran. It has bipinnate foliage made up of small, crescent-shaped leaflets with a delicately curved margin. This gives them a fern-like appearance. They close up in the evening like a mimosa.
The tree eventually develops a wide spreading canopy, with almost horizontally growing branches. It produces dense clusters of light-pink flowers in July and August that have long purple/red stamens that are very eye-catching.
Several good varieties have chocolatey coloured foliage, including ‘Summer Chocolate’ (PBR) Award of Garden Merit (AGM) and Chocolate Fountain, which also has a weeping form, as does ‘Shidare’.
What the specialists say
Liz Hughes, events and marketing, Provender Nurseries, Kent
"Albizia tend to be for the more adventurous designer but could definitely be utilised more, as it is hardier than people think. It is a late developer though and tends to look good in the late summer months.
"The variety ‘Summer Chocolate’ has certainly gained in popularity over the last few years, with the chocolate feathery foliage appealing to many. Reaching only 4m in height, it is also a perfect choice for the smaller garden.
"Albizia like sun, sun, sun and very good drainage. If you can provide these, your Albizia will be as happy as can be."
Stephanie Dunn James, assistant managing director, Trees for Life/ Frank P Matthews, Worcestershire
"Albizia, or the silk tree, are mimosa-like, small umbrella-shaped trees with feathery foliage and stunning fluffy-headed flowers. Flowering usually in July, the stamens appear much larger than the petals and look like silky threads. They are very attractive to bees and butterflies.
"The classic A. julibrissin Ombrella is quite spectacular with its powder puff-like tropical flowers.
A. julibrissin Chocolate Fountain is a stunning alternative. It’s a purple weeping form, perfect for smaller spaces, with delicate pink flowers.
"Albizia grow best in warm, sheltered sites on well-drained and even impoverished or slightly dry soils."
A. julibrissin f. rosea - image: Floramedia
Ian Garland, owner, Grangehill Landscapes, London
"It’s a lovely tree but very rarely specified as most people either don’t know it or have tried it and lost it over a cold winter. But for a warm, sheltered garden it could really become a showstopper.
"As the species and its varieties are between just four and six metres in height, it could be a feature tree for small gardens. The eventual spread will be greater than the height though, so this should be considered when choosing a location. That habit means it looks like an unfurled umbrella, which I think is quite striking.
"The standout variety has to be ‘Summer Chocolate’, with its chocolatey brown foliage. I haven’t grown it but I like the sound of A. julibrissin ‘Evy’s Pride’ because of its autumn colour and vigour."
Species and varieties
A. julibrissin, the silk tree, is a beautiful, exotic-looking small tree from China with bipinnate foliage and masses of pink, slightly scented inflorescences in summer. Likes a sunny spot in well-drained and even impoverished soil. Can be grown in a border, as a specimen in the lawn or against a wall and can even be trained as a bonsai. Height: 6m.
A. julibrissin Chocolate Fountain is a strong-growing, weeping form with deep-burgundy/purple foliage. It produces pink bottlebrush-like blooms in the summer months. Height: 5-6m.
A. julibrissin ‘Evy’s Pride’ is a vigorous selection with foliage that starts off bright-green in spring and turns reddish-purple in the autumn. Stunning large, fluffy pink flowers are produced from July to September. Height: 5-10m.
A. julibrissin f. rosea AGM (H4), the pink silk tree, is a broadly spreading, medium-sized deciduous tree with large, mimosa-like bipinnate leaves. It produces fluffy rose-pink flower heads with prominent stamens in summer. Height (after 10 years): 4m.
A. julibrissin Ombrella = ‘Boubri’ (PBR) is a small tree with dark-green leaves. It produces beautiful pink flowers in July to September. Height: 3m.
A. julibrissin ‘Shidare’ is a majestic weeping form with the usual attractive pink julibrissin flowers. Height (after 10 years): 4m.
A. julibrissin ‘Summer Chocolate’ (PBR) AGM (H3) is a large shrub or small tree with a domed crown when mature. It has burgundy/brown, bipinnate foliage and creamy powder puff blooms with pinky-purple stamens in summer. Gives off a pleasant melon scent. Height: 6m.
A. julibrissin Tropical Dream = ‘Pos 1’ is said to be one of the hardiest Albizia because it was selected from a group of trees in Seoul, South Korea, in high-altitude conditions that went down to -20°C. It flowers over a long period, from July to mid September, with large numbers of long-stalked fluffy pink flowers. Height: 5-6m.
A. kalkora is a vigorous tree that produces delicately textured bipinnately compound foliage and produces masses of feathery yellowish-white flowers with pink stamens. Rarely seen.
Thank you to Floramedia, which supplied the images for this article from its photo library www.floramedia-picture-library.com