Black Locust

Common name Black Locust
Botanical name Robinia pseudoacacia
Family Fabaceae
Natural range South-east USA
Mature height 10-15m
Form Upright spreading
Likes Growing spines on young branches/leaves
Dislikes Shady spots/wet soil
Where to plant Full sun
Known for Useful timber and invasive characteristics

**Getting to Know the Robinia pseudoacacia: A Rough Gem?**

What’s That Tree? Meet the Black Locust

Meet the Black Locust, known to the scientific community as Robinia pseudoacacia. This species, part of the Fabaceae family, hails from southeast USA. Displaying an upright spreading form, the Black Locust can grow to heights between 10-15m.

What Are the Likes and Dislikes?

The Black Locust has an interesting penchant for growing spines on its young branches and leaves. It prefers to bask in the full sun, while shady spots and wet soil are not its favorite.

Is the Black Locust an Acacia in Disguise?

The Black Locust often gets mistaken for an Acacia, thanks to its broad-spreading form and bi-pinnate leaves. Even its botanical name, False Acacia, might trick you into thinking it’s an Acacia. In some ways, you wouldn’t be completely wrong—they’re both members of the Fabaceae family, a fact evident in the seed pods formed post-flowering.

How Do These Trees Fare in Australia?

Despite its North American roots, the Black Locust enjoys considerable popularity in Australia. This robust deciduous tree, capable of reaching around 10m tall, has a particular appeal. You’ll often spot the yellow-leaved cultivar ‘Frisia’ enhancing Australian gardens, while the mop-top variant ‘Umbraculifera’ is a common sight along streets and avenues.

What’s the Historical Significance of Robinias in Australia?

In the era of Australia’s gold rush, miners highly prized these trees for their structural support in mining tunnels. Their resistance to rot, even when soaked, was a major benefit. If you wander into areas of Victoria’s High Country, where old gold-digging sites lie, you’ll see these trees still self-propagating, centuries later.

What’s the Story of Black Locust in North America and Europe?

European pioneers in North America shared a similar appreciation for the Black Locust. Its dense, hard timber that could resist rotting longer than any other native wood, even as an in-ground post, was a coveted attribute. On reaching Europe, the Black Locust thrived in the warm, long summers of southern France and central Europe. It became a valuable asset for beekeepers, producing high-quality nectar.

Is the Robinia More of a Friend or a Foe?

Despite its usefulness, the Black Locust can be quite the aggressor. It proliferates relentlessly through seeds and suckers, earning itself a reputation as an ‘invasive’ species. This status holds true in Australia as well. Nevertheless, it continues to be valuable for preventing erosion and colonizing areas of disturbed soil. Thanks to its aggressive roots and nitrogen-fixing abilities, it can grow quickly even on poor soils.

Quick Facts

Despite its botanical name, the Black Locust is not an Acacia but is related to it as a member of the Fabaceae family.
It was highly valued during the Australian gold rush for its rot-resistant properties as tunnel support.
Despite being native to North America, it’s considered an invasive species due to its aggressive spread.