Robinia pseudoacacia ‘Umbraculifera’ is a special variety of black locust tree. It sprouts dense twigs and leaves from the crown of the tree and forms a shrubby, umbrella-like canopy that is very dense.
Planting and growing tips listed here will help you take proper care of your Robinia ‘Umbraculifera’, whether grown in containers or in the ground.
Height?– max 20 feet (6 m)
Exposure?– full sun
Soil type?– ordinary
- All about the acacia tree
Season for planting
- Fall is the best season since it allows for roots to develop before the spring vegetation occurs.
- However, spring is also perfectly fine, especially if purchased in a container.
Full sun is where Robinia pseudoacacia ‘Umbraculifera’ will thrive.
- Its fun umbrella-like shape will grow evenly all around.
- Shade from buildings or nearby trees will cause the tree to grow asymmetrically.
Soil type for Umbraculifera false acacia
There isn’t any special requirement for this variety to grow.
- Simply avoid waterlogged soil.
- No need to fertilize.
Robinia pseudoacacia Umbraculifera pruning
The shape of this ‘Umbraculifera’ false acacia is perfectly natural. There is no need for any pruning.
The only exceptions are:
- if you must reduce the size of the tree. If so, prune into a sphere during the dormant season (winter/dry season).
- if the Robinia ‘Umbraculifera’ is growing in a pot. See below if that’s the case.
Container growing of Robinia Umbraculifera
Robinia pseudoacacia is usually a tree that grows rather tall. Luckily, this particular ‘Umbraculifera’ variety retains its magnificent round shape in all growing situations.
This makes it ideal for growing in a container, garden box, or large pot on a balcony or terrace.
Growth will slow in a pot, but to make sure the plant survives for many years, you must perform two tasks every year or two: pruning and repotting (or replenishing soil nutrients).
Pruning Robinia Umbraculifera
For the shape to stay round, you must prune the tree-turned-shrub yearly.
- End of fall or during winter is fine.
- If during winter, choose a period where it won’t freeze for about a week during and after pruning.
Retain the round shape: prune long branches that extend too far out to one side or the other. At the end of the pruning, the shape must look like a sphere from all sides.
Repotting your Umbrella acacia
Upsize the pot every two years until it becomes difficult to do so.
- More on repotting tips and tricks
From that point on, do your best to replenish soil nutrients. There are several ways of doing this:
- topdressing – remove the topmost soil layer and replace with fresh soil mix amended with mature compost.
- liquid fertilizer – any all-purpose fertilizer will do, but best is to make your own fermented fertilizer tea from any of the possible weeds you might have growing in your garden.
Learn more about R. pseudoacacia Umbraculifera
“Umbraculifera”, the scientific name of this variety of Robinia pseudoacacia, means “like an umbrella”. This is because of the silhouette of the tree, which is like a dense, round clump. As the tree ages, the shape shifts from a near-perfect sphere to an umbrella-like form.
- This is perfectly natural and doesn’t even require any pruning or topiary skills!
The best way to highlight this tree is to plant it alone in its own growing bed, in full sun. That way, it can fill out naturally in all directions without being pressed by neighbors.
Smart tip about Robinia Umbraculifera
Both plant mulch and mineral mulch will make this even more appealing. The definite shape will be highlighted against the uniform background!