Mimosa Trees: Exotic, Aromatic, and Potentially Threatening?
The mimosa tree, sometimes called the Persian silk tree, is a legume and can help enrich the soil where it grows. The Persian name means “night sleeper,” and in Japan it is known as the sleeping tree. 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 those of a fern or a palm frond. The flowers are anywhere from pale to deep pink and form in clusters that look like fine silk threads. They form long pods that are 5-7 inches long and enclose the seeds.
The technical name, Albizia julibrissin, is native to eastern and southwestern Asia, but 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, nor have they ever gotten out of control that I know of. 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 an invasive species 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 it 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 it was in 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.
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 taken into consideration. It's important 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 that is 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 it's 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 shade that is very pleasing. 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 is a serious soilborne fungal disease that spreads through a few different routes. A tree that is 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 are thick-walled, dark structures that allow the fungi to survive inactive in the soil for an extended period of time. 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 at all times 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 family Fabaceae.
- 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.
Mimosa TreesClick thumbnail to view full-size
What Is Mimosa Strigillosa?
It has come to my attention that there is a good deal of confusion regarding mimosas. Some information states that the seedpods are often used as livestock feed while other information says the seedpods and seeds are the most noxious part of the plant, and can, at the extreme, cause death.
For that reason I am including information about mimosa strigillosa, also called powderpuff mimosa (because of its soft flowers) or sunshine mimosa (it prefers full sun but can do quite well in shade).
What Is Mimosa Strigillosa Used For?
Mimosa strigillosa or mimosa powderpuff is a ground cover and is indeed used as food for livestock such as cattle and chickens or turkeys, and is equally utilized by wild fowl, deer, caterpillars, and honeybees. No part of this strain of mimosa was listed as toxic, and its parts are regularly utilized as food by both domestic livestock and wild animals.
What Are the Growing Conditions for the Strigillosa Species?
Mimosa Strigillosa is a very hardy plant and can withstand severe conditions. Like the mimosa trees, this ground cover readily adapts to most soil types and can withstand drought very well. While it does grow well from the seeds it produces, the stems also spread and form an overlapping vegetative mat making it an excellent way of controlling erosion.
Important Notes About This Plant
I am including photographs of this type of mimosa so that my readers may learn to recognize it. It does not grow into trees or bushes and remains fairly close to the ground, usually three to four inches high, but rarely as much as 12 inches high. The USDA (United States Department of Agriculture) says it is not considered an ecological threat or in any way invasive, yet the University of Florida Lee County Extension office says it “is difficult to control in restricted areas and is best grown with definite boundaries, such as pavement or sidewalks, where it can be more easily edged.”
Note: Please see my list of references below, and by all means, check them out for more information on this plant and any questions you may have about it. Whenever you have questions about plants, gardening, lawn care, animals (either domestic or wild), pesticides or other chemicals, food, food additives or preservatives, recipes, or a huge variety of different issues and subjects relating to plants or animals, consult your local county agricultural extension office. They provide a free service provided by the county's tax dollars. Every state and most counties have one.
Facts About Mimosa Strigillosa
- Alternate names include powderpuff, herbaceous mimosa and sunshine mimosa.
- Powderpuff is utilized by both domestic livestock and wildlife. It serves as a food source for cattle, goats, sheep, and deer.
- Powderpuff is a native, warm season, perennial legume which may reach up to eight inches in height.
- Powderpuff is also an important plant for pollinator habitat. Bees utilize powderpuff as a pollen source while little sulphur butterfly caterpillars (Pyristia lisa) feed on the foliage.
Mimosa PowderpuffClick thumbnail to view full-size
Different Mimosa Species and Origins
Thar desert of the Indian subcontinent
the central United States
Clouds of Profuse Soft Pink Blossoms: My Experience With Mimosas
Hummingbirds, butterflies, deer, birds, and bees, all love mimosa trees. They smell wonderful, and they are my favorite trees in Texas, which is the first place I am aware of having seen them. I always look forward to their blossoms, which usually appear in late spring and last for several weeks.
Some of the places where I have lived in Texas have had mimosa trees right near my front door. One evening, about dusk, I was going out to run an errand and I just happened to look up for some reason. There seemed to be a fairytale like cloud of pink cotton candy above me due to the folding of the mimosa tree’s leaves, making them invisible in the low light. The limited light made the feathery blossoms appear like soft fluff suspended in the air, and the smell was intoxicating.
The first vision of those blossoms has remained with me for years. That was when I first learned that the leaves of the mimosa fold for the night. I often wish I could have gotten a photo, but it probably would not have turned out well in such low light anyway.
- U.S. Dept. of Agriculture
- University of Florida Lee County Extension
- Garden of Tomorrow, John Minton
Questions & Answers
It's mid-May and my mimosa tree has no leaves. Is it dead?
If it still has no leaves by the first week of July, it very well may be dead. Most of the mimosa trees here in North Texas don't blossom until late May or the first part of June. Be patient. Mimosa trees are not trusting that bad weather is over. They like to be positive. Many times here in North Texas we have had everything leafed out and blossoms everywhere only to get a hard freeze, and all the blossoms and new leaves are burned off and must start all over. Mimosas seem to know this.
For how long does the mimosa tree produce these poisonous seed pods and during what time of year?
Like most plants, seeds are produced towards the end of the blossoming stage. Mimosa seedpods may mostly remain on the tree all winter and fall just as the new blossoms are beginning. A bagger lawn mower can make the job of picking up the seed pods easier as you can do it at the same time you're cutting your grass. Between cuttings, you may want to check for new fallings of seedpods if you have pets or young children prone to putting the seedpods in their mouths. Personally, I have never heard of anyone being affected by the seedpods, so putting them in one's mouth can't be very common.
When do you plant a mimosa tree from the pot that it came in, into the ground?
When you are certain the last freeze of the spring season has passed, it should be safe to plant your tree in the ground. Most of the time mimosa trees will grow like weeds and once it is established and starts producing seed pods it will likely fill your yard with more mimosa trees unless you remove them or cut them along with the grass.
If you aren't sure if the last freeze has passed, plant the tree sometime during the month of June so it will have time to get used to its new situation before cool weather arrives again.
How do you trim a Mimosa tree?
Trim it like any other tree, lopping off branches that hang too low, shortening branches that you consider too long. I have never done anything special when trimming mimosa trees and they have always come out well. As I have said, they grow easily and fast, and recover from most things very well.
© 2012 C E Clark