Starting a mimosa tree from seed

Many years ago, I received a few mimosa tree seeds from a friend. I was familiar with the tree, even though it wasn't that popular in our country. I had already seen some of the trees blooming, with their beautiful feathery flowers and I knew I had to have one in my garden. Although all my American friends are always complaining about the mess it makes on their lawns, when the flowers are fading and falling to the ground, I didn't give up until I had a mimosa tree in my garden.
I sowed a few seeds in a pot and started to water them regularly. Soon, a small plant started to grow. It grew very fast, so in the spring, it was tall enough to be planted outside.
It was a little difficult to find a good spot for the small mimosa tree in my garden, because I already had lots of trees and bushes. But I really wanted it grow in the front yard near the fence, so everyone could see its beauty. I decided to plant it in the middle of the strawberry patch, which was all clear of any tree or bush and in the front garden. It was only a small tree, which grew better without other trees or bushes around.

My baby mimosa tree surrounded by strawberry plants

The following spring, there was no sign of the baby mimosa, yet it sprouted again from its small roots. Unfortunately, I had to move it from there, because of some utilities which had to be buried in that very place - they actually destroyed the whole strawberry patch! I managed to find a good spot for the mimosa tree, next to a silver fir. I took care for it to plant it in full sun, so it could grow very well.

Three years mimosa tree in its new spot

Mimosa tree facts

It is known that the mimosa tree grows fast and very tall, up to 52 feet (16 meters). Its crown is very large. This is what I had in mind when I chose the spot for planting my small mimosa tree seedling. It was close to the fence and right next to the silver fir, not to mention a lilac bush on each side, I knew it would grow tall and that it would overgrow the fir and the lilacs by far. But that's what gave me trouble, the mimosa tree's growth!
Mimosa tree, also called Persian silk tree - on its Latin name Albizia julibrissin - is a deciduous ornamental tree, in the Fabaceae family (bean family) Albizia genus, native to southwestern Asia, in Iran (known as Persia, in the past), Korea and China. Its first Latin name honors the first man who brought this tree to Europe, an Italian noble man, Filippo degli Albizi; the second name means 'silk flower' because of their feathery silky pink and white flowers. The Mimosa tree's bark is greenish grey, its leaves are bipinnate, looking like feathers, with 20-30 pairs of small leaflets on each pinnae. The leaflets have an interesting property, to go to sleep during the night or during rains. The leaflets are actually bowing downward and closing when the sun sets. This is very similar to a number of plants termed 'sensitive plants'. The leaves fold up or close when disturbed.

My mimosa at sunset with closed leaflets

Invasive Mimosas

The flowers have long and dense white and pink stamens, that look like silky threads, which are a good source of nectar for butterflies and bees. In the fall, they fade and numerous seedpods appear with lots of fertile seeds inside, which stay viable for a long period of time and are resistant to drought. They germinate very well when they fall on the ground which is why the tree is considered an invasive species in many parts of the world. The many seedlings often crowd out native plants. I knew that long before I had a mimosa tree in my garden, but it didn't scare me, because I wanted it so badly!

Winter protection for mimosas

I knew all those things and yet I didn't consider the most important thing, that it is a semi-tropical tree and not adapted to colder regions. When I checked on the map, its native areas of China, Korea and Iran are more southern than Romania. I always saw mimosa trees growing inside the city of Bucharest, in parks and in people's gardens where it's much warmer than in our village. I began to understand it after the first winters, when my mimosa tree died back - again and again - to the ground. In the spring its branches were always dry, with a pale wood color and mildew spots. Every spring I've been scared, that my mimosa tree died! I always let it stay like that until June, hoping that it would sprout back again. And it always did! I used to cut back all the previous year's dead branches and let the new growths thrive. They always grew very fast, bending over the fence - yet, no flowers. I realized that the deep freeze killed the branches, because it is just a young tropical tree, therefore not hardy. However, there is a hardy Albizia cultivar, the Albizia julibrissin f rosea, which is more cold tolerant than the original species. It is also called the pink silk tree, because of its only pink flowers. If mine is one of these trees, I wouldn't know, because I haven't seen a flower on my tree yet.

I had another bad experience with two magnolias - which I managed to kill, by not covering them enough during winter and from those I've learned a lot about plants' winter protection.
I've always used the park gardeners' example and learned from their work in the park. When they started cutting back the roses, I would cut back mine too; if they would trim back the bushes, I would do the same. So, when I saw how they covered the small magnolias, I followed their example. Only I didn't pay attention to the cover they were using, which was a thick fabric made from a braided plant vine. After losing my magnolias, I thought about that a lot and realized that I needed to find something similar to what the park gardeners were using as a cover. I had some straw carpets, which we have been using to lay on at the beach. They seemed perfect for covering my most sensitive plants. I had a cherry laurel bush and a small Japanese maple to cover and so there went the two straw covers. After having good results with these winter covers, I thought maybe I should cover the Mimosa tree too during winter, to keep it alive, but what should I use? I remembered I had some straw table covers, which I wasn't using anyway. They were rather small and short, but they could be of some use and better those covers than nothing! And so, there I was, climbing over the fence and holding tight to the mimosa tree, in the middle of a strong and cold November wind, which was about to bring the first frost and maybe snow. How can I always be so careless and put things off till the last minute? I tied up the small straw layers around the mimosa branches, with a cord, and prayed that it will be enough for the branches to survive during winter.

My mimosa tree was covered during one hard winter

The winter passed, with several deep freeze periods, but then the spring came along, with sun and warmth. I uncovered all the plants and the Mimosa tree was dead again. The good thing was that it produced more long sticks, which I could use to hold the tomato plants. As usual, I let the dead branches stay on the tree until the new sprouts appeared, then cut them back and let the new sprouts grow. Most of the Mimosa trees I'd seen were mature and I didn't know whether they were planted when mature or when they were seedlings. I began to understand that my tree needs to be mature, in order to survive freezing but will it be able to grow thicker in only one summer? And then a new thought struck me, like a glorious light bulb glowing in my empty head! What if I would let the main new branch grow and cut back all other branches? This way it could grow thicker and become the tree's main trunk, before the first frost. Thus it could, probably be more resistant than several thin branches, and this is the way a tree should be anyway!

My mimosa tree grew very tall last summer
I applied the new idea and stayed stuck to it, for all summer long. I watered the tree thoroughly, during the hot summer days. The trunk became thicker and thicker and now it is like a young tree's trunk, which I'm sure will resist next winter's frosts. I'm not sure about the taller branches, which grew from the main trunk, but if they will freeze, that won't be a problem, because I will have, at least, a bare trunk, ready to start new branches.
I bet I will have flowers on my Mimosa tree next summer! Would you like to make a bet?