Acacia dealbata is a fast-growing flowering tree or shrub, sometimes called mimosa or wattle. It grows up to 12m tall and 4m wide and features large pinnate, fern-like foliage. The bright yellow flowers appear in clusters of small fuzzy spheres, like pom-poms, and have a warm, sweet fragrance. The blooms are rich in nectar and are a magnet for bees, butterflies, and other pollinators.
Where to Plant an Acacia Tree
An acacia tree is perfect for adding height interest to borders and sheltered patios. Grow towards the back of the border, where the tree can complement other plants, offering them some shade from afternoon sun exposure. A spot against a south or west-facing wall where the tree can soak up full sunlight is ideal.
When planting an acacia dealbata in a pot or container, use loam-based soil and ensure it’s placed in an area with full sun exposure, shielded from harsh weather. Pot-grown mimosa trees work well in conservatories and greenhouses, where the temperature is warm, and they’re unexposed to the elements.
Acacia dealbata needs a sheltered spot where to be protected against strong winds. A position in full sun or partial shade is best, and in neutral to acidic soil. The ground should be well-draining with moist soil.
Acacia Tree Care
Acacia dealbata is a low-maintenance tree that doesn’t demand much attention. A young tree may need to be staked to help keep it upright and offer some protection against wildlife. But other than that, a mimosa tree will pretty much look after itself.
Watering
An acacia dealbata tree’s watering schedule is largely determined by its location. Planted in the garden, the tree can soak up nutrients and moisture from the ground and only needs to be watered during particularly dry spells of weather. However, an acacia tree planted in a container needs watering more often as the soil will dry out faster.
In hot or warm weather, water the tree in the evening to prevent the moisture from evaporating away too quickly. Avoid watering the tree when it’s frosty to prevent the water from freezing and damaging the plant’s roots.
Feeding
There isn’t any need to feed an acacia dealbata tree. However, applying a mulch of well-rotted organic matter will offer your tree a boost. If you feel your mimosa tree would benefit from fertilizer being applied, an all-purpose garden feed is best.
Pruning
While an established tree only needs pruning to remove dead or damaged branches, a young tree needs a little more attention to train it into an attractive shape. The best time of year for pruning is mid-spring, once the risk of frost has passed.
Acacia dealbata can benefit from light pruning after flowering. Bear in mind that the following year’s blooms start to take shape in autumn, so it’s best not to cut the plant back after late summer.
Can Acacia trees grow in the UK?
Acacia trees are native to Australia, particularly the southeastern area of Victoria, New South Wales, and Tasmania. As such, acacias thrive best in warm regions. But, given a sheltered position, they can flourish in the UK climate.
Is Acacia dealbata hardy?
Acacia dealbata is not fully hardy in the UK but can be successfully planted and grown in the garden in southern and coastal areas, where the winter weather tends to be milder. For more frost-prone areas, plant acacias in pots and containers, which can be moved inside as the temperature drops.
Species of Acacia Trees and Shrubs
There are well over 1,000 species in the genus acacia, including Sydney Golden Wattle, Blue Wattle, Green Wattle, and Hickory Wattle. However, not all varieties will grow successfully in the UK.
Silver Wattle
Silver wattle is the acacia species that grows most successfully in this country. In fact, it has received the Royal Horticultural Society Award of Garden Merit, which is based on the plant’s performance in UK growing conditions.
Part of the acacia dealbata family, the silver wattle is an evergreen tree that blooms bright yellow flowers from late winter into early spring. The light, fern-like leaves have a purplish tinge before they mature to a rich green hue, and the bark is an unusual shade of green-grey.
How fast does Acacia dealbata grow?
Growing to just 12m tall, an acacia tree is an ideal size for planting in the garden. This is a relatively fast-growing tree, reaching its ultimate height in just 10-20 years. Some species can take on an impressive 6-8ft per year.
Acacia dealbata isn’t for every garden in the UK, especially those in northern inland areas with the coldest of winters. However, if you have the perfect spot to keep them sheltered and can offer plenty of sun exposure, these charming evergreen trees provide year-round interest and an abundance of cheerful yellow color in early spring.
