It’s now in full bloom. Some think the flowers are gorgeous and want one in their yard. Maybe if they quit mowing their lawn they’d get their wish. The mimosa is that ‘Dr. Seuss-like’ tree with spreading branches and copious delicate and fragrant pink blooms. Bees, butterflies and hummingbirds love them.
After flowers disappear, distinctive bean-like pods form, assuming flowers have been pollinated. Mimosas are self-sterile, which means another tree must be present within a few hundred yards. Pods grow to six inches long and have flat seeds inside. They usually remain on the tree during winter. Seeds can be viable for many years and usually require some type of weathering to germinate. An animal’s digestive system can suffice but seeds are toxic to many.
Botanists refer to the leaf arrangement as bipinnate. Many tiny leaflets comprise each leaf giving the tree a fern-like feathery appearance. Leaves fold up at night and during rainstorms for protection.
Though individual leaflets are small, the combined effect creates a dense canopy that keeps light from reaching the ground underneath. This forces many existing native plants to suffer from lack of light. Most turfgrasses struggle underneath them.
Sometimes called silk trees, they are members of the bean family. This group of plants has bacteria that grow on the roots and trap nitrogen for their benefit. Consequently, mimosas can grow on poor soils with low fertility. For this reason we find them everywhere.
They are fast growing short lived trees. Twenty years is an old tree. They can reach heights of 25 feet with a 35 foot spread. The wood is weak but since trees are usually small, they seldom cause damage. Mimosas prefer sunny locations but can grow in partial shade. Bloom is less under shady conditions though.
So what if we don’t want them on our property? Cut them and treat the stumps when in active growth. Concentrated Round-up works well, but you still might have a few suckers coming up from the roots away from the main trunk. You also may have them pop up on other parts of your property, since they spread by seeds and production is prolific. Keep your lawn mowed and inspect your shrubbery regularly. Plants are easy to recognize.
Is there a use for them other than their delicate looks? Yes, parts of them are edible. The flowers can be eaten raw or steeped as a tea. They are high in antioxidants which decrease the danger associated with high LDL cholesterol.
The bark also makes a useful medicinal tea. Don’t eat the seeds though. They contain neurotoxins and are toxic. According to numerous sources, the mimosa has been used medicinally to counteract insomnia and as an antidepressant. Some call it the tree of happiness.
Traditional Chinese medicine has relied on mimosa to counteract depression, anger, grief and poor memory for centuries. I haven’t found any documented side-effects of mimosa flowers and bark. However, I feel mimosa’s beauty is best taken in through the eyes and not the mouth.
Ted Manzer teaches agriculture at Northeastern High School.