Ms. Clark has a solid appreciation for hard science and likes to share interesting things she learns in the course of her research.
What Is a Mimosa Tree?
The mimosa tree, sometimes called the Persian silk tree, is a legume that can help enrich the soil where it grows. The Persian name means "night sleeper," and it is known as the sleeping tree in Japan. That is because the bipinnate leaves fold up at night and during rainstorms.
Bipinnate simply means that instead of having undivided leaves, the leaves are separated like a fern's or a palm frond's. The flowers range from pale to deep pink and form clusters like fine silk threads. They form long pods that are 5-7 inches long and enclose the seeds.
The mimosa tree—Albizia julibrissin, according to its scientific name—is native to eastern and southwestern Asia, but it does well in most climates here in the States. It is a fast-growing ornamental tree that can reach up to 30 feet or slightly more in height.
Advantages and Disadvantages of Mimosa Trees
While these trees are beautiful and powerful, their effect on the natural environment can be problematic outside of their natural ecosystem. The severity of their impact is debatable, but as environments shift, it's becoming more and more important to study these trees.
Advantages of Mimosa Trees
- The mimosa tree is cold weather tolerant and has been known to survive temperatures as cold as -25 degrees Fahrenheit.
- Nature Hills Nursery in Omaha, Nebraska, claims the mimosa tree "acts as a natural de-wormer for woodland creatures."
- From my own experience, in addition to being pretty and smelling wonderful, the mimosa trees that have been in my yard provided lots of great shade from the sun.
Disadvantages of Mimosa Trees
- Unfortunately, the mimosa tree is considered by many horticulturalists and others to be an ecological threat.
- Mimosa trees can grow in a variety of soils, produce large seed crops that travel and spread easily by wind and water, and re-sprout when damaged.
- The mimosa, I am told, is a strong competitor to native trees and shrubs in open areas or forest edges.
- Dense stands of mimosa severely reduce the sunlight and nutrients available for other plants.
I must confess that as prevalent as mimosa trees are here in North Texas, I have never seen a "dense stand" of them anywhere, and I'm not aware that they've ever gotten out of control. I have never heard anyone complain about them.
How to Care for Mimosa Trees
If you live in an area where mimosa trees are not regarded as invasive and decide to grow these beautiful trees on your property, there are several important steps to consider.
- First, plant mimosas in a well-draining, sunny site that provides lots of room for them to grow (mimosa trees grow up to 20 to 35 feet tall and 25 to 30 feet wide). If you are transplanting a sapling, replant the tree at the same level as its original site. If the soil is hard, incorporate compost or soil conditioner into the planting hole to improve drainage.
- Water the sapling when the soil is dry. Keep doing this until its roots are well established. This should take just one season. After doing this, water the tree, but only during severe droughts. Mimosa will die in soggy soil. Mulching conserves water and increases the time between waterings.
- Fertilize mimosa sparingly in spring or not at all. This tree is already a fast grower. Don't use too much fertilizer. It speeds up growth but can result in weaker branches. Make sure you use a balanced fertilizer, such as 10-10-10. I'd recommend using it at half the rate recommended on the label.
- Trim out limbs that are crowded. Cut out dead and weak branches with lopping shears. Make sure to disinfect the tool blades after each use, so you don't spread disease to other garden plants.
Important notes: Mimosas will, most likely, not last a lifetime. These trees are prone to damage from disease and insects. They will probably grow quickly, reach their peak, then decline and die in about 15 years. These trees bear long seed pods that cling fast, even through winter.
Mimosas seed freely, so you're likely to find new seedlings in your lawn and garden each spring. Be mindful of mimosa seeds. You may end up with many more trees than you wanted.
Read More From Dengarden
Tools You'll Need to Care for These Trees
$20-70 (depends on the size of the shears and the brand)
Frequently Asked Questions About Mimosas
While these trees are beautiful and might make your yard more attractive, their impact on the environment must be considered. It's essential to understand the difficulties these trees can pose before you grow one.
Are All Albizia Julibrissin Trees Invasive in the U.S.?
Simply put, yes. Also called the silk tree, Albizia julibrissin is a beautiful but invasive tree threatening the landscape across the American South (primarily Florida). The tree is originally from China, where it is balanced in the ecosystem. However, in the U.S., this mimosa tree does not help the ecosystem.
Are Mimosa Trees Fast Growing?
The mimosa tree grows quite quickly. Usually, it adds two or more feet of height per year. Therefore, it can reach its maximum height of 20 to 40 feet in just 10 to 20 years. Fast-growing means that its roots spread quickly. The faster things grow, the faster they can reshape a landscape.
Do Mimosa Trees Have Invasive Roots?
The Mimosa tree's canopy creates very pleasing shade. However, its root systems are invasive. Its root systems can lift and crack concrete. The damage that they cause can be expensive to repair.
Can Albizia Julibrissin Get Diseases?
Yes. One common disease these trees contract is Fusarium, which causes wilting. This serious soil-borne fungal disease spreads through a few different routes. A tree defoliated by this disease will produce spores long after the plant has died.
The spores will continue spreading the wilt to healthy host plants through water, air, and insects. Any spores washed into the soil via rain and irrigation will create chlamydospores.
These thick-walled, dark structures allow the fungi to survive inactive in the soil for an extended period. When tree roots from host plants grow close to these fungal spores, the chlamydospores germinate and produce mycelium, which attacks the mimosa roots, infecting the tree.
Warnings About These Trees
- The seedpods are poisonous, and the seeds within are even more so.
- Do not allow livestock, pets, or especially children to put the seedpods or seeds in their mouths. They can cause seizures and even death.
- Be sure to keep the seed pods away from animals and children. Rake them up as soon as they begin to fall, and teach your little ones and all of your children never to put the seedpods in their mouths. Do not assume an older child, or even an adult, who may be unfamiliar with mimosa trees, knows not to do so.
- The flowers and leaves are not toxic, and some people cook them and eat them like vegetables or make tea from them, but avoid the seedpods and seeds.
Facts About Albizia Julibrissin
- It's in the Fabaceae family.
- Its native range runs from Iran to Japan.
- Its average height is between 20.00 to 40.00 feet.
- Its average spread is between 20.00 to 50.00 feet.
- It blooms from June to July.
- It has been widely planted in the U.S. as an ornamental and has escaped cultivation, naturalizing in many areas of the southeastern U.S. and California.
- In the wild, it is typically seen growing in vacant lots, waste areas, clearings, wood margins, fields, and along roads.
- Its genus name honors Filippo degli Albizzia, an 18th-century Italian naturalist who introduced the genus to Italy in 1749.
- Its specific epithet comes from the Persian word gul-ebruschin, meaning floss silk, in reference to the flowers.