Get to know those sensational jacarandas better

There is nothing quite as encapsulating as walking down a street lined with jacaranda trees.

In fact, these trees are hard to miss as many streets in our community have the pleasure of making these towering plants their most beautiful focal point. That being said, it might surprise a few to read that this tree is not indigenous and is a South American native which was imported into the country originally from Argentina and later Brazil.

Most jacarandas reach maturity at about 20 years and although they have a lifespan of up to 200 years, it has been said that according to arborists in the area, those in Joburg, which are now about 100 years old, are coming to the end of their lifespans.

“This could mean that the years of purple spring seasons in Gauteng, sadly, are limited,” said local and head communicator at Hadeco Bulbs, Melanie Walker.

She shared more on these enchanting trees as she explained that the tree can be traced back to as early as 1880, “Farmers who came up north, before the Gold Rush, brought with them oak, walnut and jacaranda seeds among others from the Cape.”

Walker added that although Pretoria is called ‘The Jacaranda City’, there are more of them found in Johannesburg – with Pretoria having about 65 000 to 70 000 jacaranda trees making up about 16% of their urban trees.

“Apparently, it was one William Nelson, a nursery owner living in the country in the 19th century, who was responsible for lining our Joburg streets, in particular about 106km worth in the suburb of Kensington,” she explained.

Though people always think of the flowers as being purple, lilac would be closer but these trees do produce flowers of other colours, most notably the rare white variety. Their peak flowering time is mid-October to mid-November and has been known to flower from September, though this is usually only after a milder winter.

Yet, even though they’re not indigenous, Walker said they’re not necessarily harmful to other plants, “But they can invade watercourses, sucking up more water than is available to endemic and indigenous flora.”
They have really strong root systems which is one of the reasons they outcompete local species, such as native grasses, and very few other species can grow under them.

Walker concluded jacarandas have been on the invasive list for a number of years, classified as a category two or three invader, depending on the area, which means they aren’t allowed to be propagated, but they don’t have to be removed.

“In urban areas such as Johannesburg, they’re apparently no longer declared invasive, though there is debate about this.”

However, national policy is quite clear that jacarandas are no longer considered invasive in urban areas. In 2014 it was decided to adopt a more balanced approach and limit the categorisation to certain regions where it could, in fact, cause damage to the ecosystem, for example in Mpumalanga.