The mimosa tree, cultivated for ornamental purposes, reaches its peak splendor in the month of March. With its colorful blossoms, it paints our landscapes in yellow, from north to south. Symbolically associated with International Women’s Day, celebrated on the 8th of March, it is not uncommon for this flower to be given as a gift on this international occasion. The purpose of this day is to commemorate the many social and political achievements women have made over time, while also acknowledging the discriminations and violence that many of them still face today. But let’s return to our flower: have you ever thought about giving an entire mimosa tree instead of just a simple bouquet?
In this article, we will reveal everything you need to know about growing this plant in your garden or in a pot. Obtaining beautiful and thriving flowers without using pesticides is not difficult at all; you just need to follow the right guidelines.
As always, let’s start with the characteristics of the plant. So, let’s take a look at the tips for planting, the ideal soil for growth, tree care, and discover the periodic pruning operations.
The Mimosa Tree
The term mimosa identifies a genus of plants, herbaceous or shrubby, belonging to the botanical family Fabaceae. There are over 700 species within this genus. The ones of our interest, widely cultivated in Italy, are: Acacia Dealbata (common mimosa) and Mimosa retinoides (four-seasons mimosa).
As a species, the plant is native to the Oceania region, particularly Australia and Tasmania. In these territories, the shrub grows wild and can reach up to 30 meters in height. The plant arrived in Europe in the early 19th century, along with another well-known plant, the eucalyptus. Due to its characteristics, the tree has adapted very well to the Italian climate, especially in milder regions. In some parts of the peninsula, they can grow up to 115 meters, while in colder regions, they are usually cultivated as potted shrubs, with smaller dimensions.
In some areas, the plant has acclimatized so well that it forms small spontaneous groves. The yellow-colored sight during the flowering periods is fantastic.
Among the species, the Acacia Dealbata, or silver wattle, is the most widely cultivated in our country. The tree is evergreen with a shallow but well-developed root system. It is often used to retain soil on slopes. Its flowering occurs from the end of January to the end of March, and it is known for heralding the arrival of spring.
The branches, green in color, have a finely velvety surface. The foliage consists of numerous pinnate leaflets, arranged in 30-40 pairs. During the day, these leaflets are open and full, and they close and fold at night. The typical yellow-colored flowers are grouped in inflorescences and spherical heads, forming bouquets or terminal clusters.
These delicate flowers resemble small tufts and have showy, bright yellow, and feathery stamens. However, when cut, they tend to wither quickly.
The M. Retinoides, or four-seasons mimosa, blooms throughout the year. The peak of its floral development occurs between May and September. It is a more robust species that adapts well to any type of soil, making it often used as rootstock.
How to Cultivate a Mimosa Tree
As mentioned, the mimosa prefers a mild climate. However, it does not tolerate prolonged freezing during the winter. It suffers greatly with temperatures below -5°C, and its survival may be compromised if temperatures drop below -10°C. For this reason, it is cultivated in pots in colder regions. This way, it can be protected from intense cold by moving it to a sheltered area, such as under a veranda.
Keep in mind that mimosas are not indoor plants. If kept indoors permanently, they would suffer from the unnatural heat of the heating system. Another characteristic of the plant is its delicate branches, which can easily break in the wind. Therefore, it is advisable to place the tree in a sunny and sheltered area of the garden.
When deciding to plant a mimosa tree, pay close attention to the evaluation of the soil. The Acacia Dealbata avoids calcareous soils and prefers slightly acidic ones, with a pH between 5.5 and 6.5. Since many soils are calcareous, you can correct this characteristic by adding acidic peat to the soil, either during planting or directly in the pot, which you can find here.
Another possible solution is to choose a rootstock such as Mimosa retinoides, which is more suitable for calcareous soils.
Especially for less experienced gardeners, this tree is primarily purchased in a small pot. It can then be transplanted between March and May.
The main propagation techniques in nurseries are grafting and layering.
Planting in the Garden
- First and foremost, it’s essential to keep in mind that the mimosa tree is long-lived and can live for at least 20 years.
- Therefore, you need to perform a deep plowing of the soil to a depth of at least 80 cm. The pit’s width should be about 50/60 cm.
- On the bottom of the pit, add well-rotted manure for bottom fertilization.
- Then, add the soil dug from the pit back into it. If the soil is calcareous, remember to mix it with acidic peat. The proportion of soil to peat is 3 to 1.
- At this point, cover the manure with a layer of soil, onto which clay can be added (this will improve soil drainage).
- After the clay layer, add another layer of soil.
- Now, place a stake (such as a wooden pole) as support. The tree will need it for the first few years until the roots grow deeper.
- Now, you are ready to plant your small tree. Remove it from the pot and soak the root ball in water for a few seconds. This will ensure good hydration of the soil ball.
- Place the plant in the pit and fill it with soil, without covering the graft point.
- Water it thoroughly and tie it to the stake.
Cultivation of Mimosa in a Pot
For cultivating a mimosa plant in a pot, pay close attention to the soil mix. Place expanded clay at the bottom of the pot (which you can find here), then prepare a mix consisting of 1/3 acidic peat and 2/3 normal garden soil.
Choose a terracotta pot with dimensions of at least 60 cm in height and 50 cm in width. This will ensure fast growth and abundant flowering.
Transplant the tree into a larger pot every two years, slightly increasing the pot’s diameter. This way, you will maintain a good proportion between the root system and the canopy.
The mimosa tree, especially in its native continent, grows naturally and adapts well to dry conditions. It does not require regular irrigation, except during the first years of life in the summer. This is useful to allow the root system to establish.
For potted cultivation, the situation is different. In this case, there is a greater need for water. This applies to most tree crops forced in pots.
In any case, be careful not to create water stagnation, which can be very dangerous for the plant.
To improve soil moisture and save the trouble of weeding, you can use organic mulch.
For pruning the mimosa tree, you need to distinguish between formation pruning and maintenance pruning:
- Formation pruning of the mimosa (or training pruning) is done in the first year. This is when you choose between the bush form, which is obtained by giving prominence to the central branches, and the pyramid form, which involves shaping the tree like a cone, leaving very long branches at the base.
- Maintenance pruning is done annually, or at most every two years. It is performed immediately after flowering for Acacia Dealbata and later in spring for the four-seasons variety. This type of pruning is done to keep the plant harmonious. It involves shortening the longer branches and removing any dead or malformed branches damaged by winter.
Harvesting and Use
As we all know, this flower is associated with International Women’s Day. Gifting bouquets of mimosa is a common practice and highly appreciated, given the intense fragrance of the flowers. However, when cutting the inflorescences, be gentle and use sharp scissors (you can find suitable scissors here). Good scissors are essential to avoid tears and, therefore, damaging the branches.
Nevertheless, since the price of a tree is quite affordable, our advice, perhaps a bit original, is to give an entire plant instead of just a bouquet of flowers. This gift will not last just one day but will endure over time, remaining permanent, just like the respect we owe to women.
- Turkish Journal of Agriculture and Forestry – “Effects of mimosa bark usage on some properties of particleboard” – This study investigates the effects of using mimosa bark in the production of particleboard panels, focusing on mechanical properties and formaldehyde improvement.
- AAAI Conference on Artificial Intelligence – “Mimosa: Multi-constraint molecule sampling for molecule optimization” – The article presents MIMOSA, a method for molecule optimization that can effectively improve properties sensitive to local structural changes.
- Elsevier – Industrial Crops and Products – “Influence of impregnating wood particles with mimosa bark extract on some properties of particleboard” – This research explores the impact of impregnating wood particles with mimosa bark extract on particleboard properties, showing that it affects mechanical properties.