Mimosa trees bloom from late spring all the way through summer, so the first flowers tend to show around May and the last ones fade by August. That gives you a long stretch of color, which is why these mimosa flowers seem to stick around for months. The mimosa tree bloom time is one of the longest of any small yard tree. Warm southern regions get the show early, while cooler northern spots wait a few extra weeks before the buds open.
For most of spring you will see only feathery green leaves that fold up at night. There is no hint of color, and you might think your tree skipped a year. Then early summer arrives and the buds swell fast. Within a week or two they burst open into soft pink puffs, and those puffs cling to the branches for weeks. The change from plain green to full bloom moves fast enough that you notice it day to day.
Each bloom looks like a silky pom-pom about 1 to 1.5 inches across. These pink powder-puff flowers are built from dozens of fine threads rather than flat petals, which gives them that soft, fuzzy shape. Look close and you will see the threads shade from white near the base to bright pink at the tips. They give off a sweet, light scent that pulls bees and hummingbirds into your yard all day. That silky feel is also where the tree earns its other name, the silk tree.
Spring
Branches leaf out with feathery green fronds that fold at dusk, but no flowers show yet.
Early Summer
Buds swell and open into pink puffs, running from late May into June and July.
Late Summer to Fall
Flowers fade and flat straw-colored seed pods form, ripening from August into September.
A single flower head only lasts a few days before it dries and drops. The tree makes up for it by opening fresh buds in waves across the whole season. So while any one bloom is short-lived, your tree as a whole stays pink for six to eight weeks in a good year. Give it a warm, sunny site with steady water and that window can stretch even longer.
Your exact mimosa tree bloom time shifts with region and climate more than most trees do. In the warm South, you may see flowers open in early May and run deep into August. Further north, your tree can hold off until June and then finish sooner. A hot, early spring pushes the whole schedule ahead by a week or two, while a cold, wet start drags it back. A young tree also blooms later than a mature one, since a mimosa often needs a few years before it flowers at all.
Heavy bloom means heavy seed. Rake up the flat pods and any sprouting seedlings each fall, or one tree can spread across your whole yard within a few seasons.
The flowers also set you up for a messy fall. Once the blooms fade, your tree loads its branches with flat, straw-colored seed pods about 6 inches (15 cm) long. They dry to a pale straw color and hang on well into winter. The pods ripen from August into September and spill out plenty of seed. Plan for the cleanup, and pull any seedlings you find, because a mimosa spreads fast where the pods drop.
If you want to catch the peak, watch the buds in late May and early June. That is when most trees hit full color and the scent is at its strongest. Give your tree full sun and it rewards you with the heaviest bloom, though you also get the most seed. For less cleanup, snip off the spent flower clusters before they dry into pods.
Read the full article: Mimosa Tree: Beauty, Care, and Invasive Truth
