Mimosa Silk Tree

If you need to garden in a hurry, fast-growing trees are a must. Sadly, many of them are simply sticks with leaves, that do grow fast, but don’t have the grace and beauty of trees that grow more slowly. While the Mimosa Silk Tree is fast-growing, adding a good 3 feet of extension every year when young, it is also amazingly beautiful. The ferny leaves on a broad umbrella of branches; the remarkable and unique pink fluffy seed heads; and even the long seed pods that decorate it in winter – all these things make for an outstanding, fast-growing plant for new gardens, and older ones too, bringing beauty and interest.

The Mimosa Silk Tree grows quickly into a small tree with a broad, spreading crown like an open umbrella. With its widespread branches it is ideal as a quick-growing shade tree for a lawn or patio, where in just a few years it will give a circle of shade big enough for outdoor dining. In time it will exceed 20 feet in height and spread, sometimes reaching 50 feet, but typically staying quite a bit smaller. It can be grown either as a tree with a single trunk, or as a multi-stem tree. You can make this choice once it is established, and then prune it to give you the look you want. As a multi-stem tree it grows into a broad vase-shape, and it is wonderful for background planting, in semi-natural areas, and for planting in sunny, dry places. It is also a good choice for a tree in a large pot, where it will quickly produce a lovely mature look.

The bark of the stems is smooth and greenish-gray when young, turning darker gray-brown and developing long vertical stripes of lighter brown in older wood. The foliage is extraordinary beautiful and interesting. Each leaf is 10 to 20 inches long, and 5 to 10 inches wide, with a green central stem carrying 4 to 6 shorter stems along each side. Those stems in turn carries 20 to 30 leaflets, ¼ inch long, along each side, giving the leaf a ferny, very divided look. Remarkably, the leaflets can move, and every night this plant ‘goes to sleep’, with the leaflets folding up and hanging down. No wonder Persians call it shabkhosb which means ‘night sleeper’, and the Japanese call it nemunoki, the ‘sleeping tree’. The leaflets will also fold during rain, and when the leaves are shaken, so when you receive your tree it will probably be sleeping inside the box. The leaves are a rich mid-green, and they give the Mimosa Silk Tree a beautiful airy look.

The Mimosa Silk Tree is in bloom for weeks and weeks, from June or July onwards, looking wonderful and very exotic. Along the branches, at the end of each growing tip, clusters of many strange flowers appear. The petals are very small, and hardly visible. Instead it is the stamens – the pollen-bearing parts of the flower – that are long and showy. There are hundreds of them, each one bright pink, with a tiny yellow tip of pollen. The look is like the crest of an exotic bird, and a tree in bloom is glorious. The blooms give out an exotic sweet fragrance, and bees, butterflies and hummingbirds all love to visit them. When the flowers finally end, they are replaced by 7-inch seed pods, looking like flattened bean pods, which turn from green to brown and last well into the winter, long after the leaves have fallen.

The Mimosa Silk Tree grows best in areas with hot summers, and it is tolerant of both humidity and dry heat.  It is very drought resistant once established, although for rapid growth regular deep watering is recommended if it is planted in a very dry location. Any well-drained soil will suit it, from sand to clay and from very alkaline to acidic. This easy tree grows almost anywhere. It has no pests, and deer leave it alone. Avoid wet areas, as this can lead to a disease called wilt, so always plant in a drier part of your garden. It is hardy in zone 6, and really thrives in zones 8 and 9. In areas with cooler summers the tips of the new branches may not ripen fully before winter comes, so some trimming may be needed in spring to remove dead tips, especially on younger trees that are growing very vigorously.

The Mimosa Silk Tree is also called the Persian Silk Tree or the Nemu Tree. It is not a ‘mimosa’, which is an Acacia tree, and it is called by botanists Albizia julibrissin. It is a unique species in the large Pea family, growing wild in Iran, and westward all the way to Japan, although it now grows naturally in many countries. It was introduced into Europe long ago, in 1749, by the Italian naturalist Filippo degli Albizzia, who it is named after. This tree is always in high demand, from gardeners who like their trees fast-growing and exotic. Order now, while we still have stock available – we will usually ship it to you the very next day.