The term mimosa commonly indicates a shrub belonging to the genus of acacias, in particular the acacia dealbata, whose small yellow flowers are usually donated to women on the day of their feast.
Mimosas are large shrubs, or even small trees, belonging to the fabaceae genus; they are now widespread in the wild in most of the Italian peninsula and the Mediterranean, but have distant origins, in fact they are plants native to Australia, from which they were imported in past centuries. The use of mimosa branches for Women's Day is simply due to the fact that these plants produce flowers in profusion towards the end of winter and it is therefore easy to get them on Women's Day, March 8th.
Those commonly called mimosa flowers are actually spherical inflorescences, which bring together very small canary yellow flowers, very decorative, intensely scented; the flowers are produced at the apex of the branches, on the thinnest twigs, and bloom in succession, starting from those closest to the stem. The flowering of the mimosa can last a few weeks and begins with the first slightly long and not too cold days, from January to March; in places with mild winters, mimosas produce flowers from the beginning of January, while in the cooler areas, flowering occurs from the second half of February.
Acacia dealbata, popularly called mimosa, is a tree that, although not native, is now widespread in our country both in cultivation and as spontaneous, especially in mild climate areas. In fact, it is fully a characteristic element of the Ligurian Riviera, of the shores of the great lakes and of all the coasts of our country. Although it has become a little invasive, it must be admitted that its cheerful and fragrant flowering reveals itself every year an inevitable symbol of the arrival of spring, giving liveliness to the landscape and awakening the first pollinating insects.
On the Riviera di Ponente it is also widely grown and collected for floriculture purposes: its demand increases exponentially in correspondence of 8 March, Women's Day, to which it is inextricably linked.
The mimosa is native to Australia (which still considers it a national symbol today). In particular, acacia dealbata is endemic to temperate and fertile Tasmania.
The subfamily of Mimosaceae (belonging to the Leguminosae family) includes about 450 species of acacias coming mostly from the tropical and subtropical regions of Oceania, Asia, Africa and the American continent. They are mostly trees, however those that form beautiful bushes or that have climbing habit are not rare.
They arrived in Europe at the beginning of the 19th century and spread very quickly, given their adaptability and often very vigorous growth (some can reach 8 meters in height in the first year of life!). However, they are not very long-lived plants and are often irreparably ruined by anomalous frosts.
Acacia dealbata occurs mostly as a tree or shrub. It is characterized by a beautiful persistent foliage: the leaves are bipinnate, up to 12 cm long and formed by 15-20 elements, in turn divided into 30-50 silvery gray leaflets, similar to feathers. The branches can be more or less thorny. The flowers appear at the end of winter (February-April): they are grouped in panicles comprising 10 to 200 globular and soft flower heads, with yellow-golden or white stamens, very fragrant. The fruits are collected in pods that ripen from mid-summer to late spring.