Albizia julibrissin 'Summer Chocolate'
October 2009
Just as the change in seasons brings out sweaters and jackets on people, many trees take on a different look as their leaves turn color. One tree relatively new to Haverford College Arboretum, however, doesn’t wait until fall to show off maroon-purple foliage.
A new cultivar of Albizia julibrissin, the Mimosa or Silk-tree, recently was brought to this country after its discovery in Japan. The new leaves of ‘Summer Chocolate’ emerge purplish green, then turn to maroon for the remainder of the growing season.
The straight species of Albizia is native from Iran to China. Its long, compound leaves made up of many thin leaflets give it an almost tropical look. The seeds develop in thin pods, so botanists place it in the Fabaceae, or Pea Family of trees.
Summer’s heat brings out the small puffs of pink and white flowers. The tree is a fast grower but stays short, only reaching about 20 feet high and 35 feet wide. Albizia likes full sun and is tolerant of drought conditions, poor soil and wind. Its toughness, together with its handsome outline and fluffy summer flowers, may tempt the home gardener.
But beware; the pretty Mimosa is more like a weed than a tree. The seeds of the straight species tend to root everywhere. It’s also susceptible to webworm infestations, leaf spot and rust.
‘Summer Chocolate’ holds the promise, however, of all the beauty without the bite. This cultivar must be grown from a graft or bud. Our tree, planted just to the left of the steps leading into the Bookstore entrance of the Whitehead Campus Center, was a gift from Steve Mostardi of Mostardi Nurseries in Newtown Square. He is a judge for the Gold Medal Plant Committee of the Pennsylvania Horticultural Society. The beauty of this small tree and its lack of viable seeds may earn it future placement on the list of plants recommended to homeowners. Happily, we’re a test garden for Albizia julibrissin ‘Summer Chocolate’ and hope to help bring it to a wider audience.