Ailanthus altissima – Quick Guide to the Tree of Heaven

If you’ve ever walked through a city park or a roadside ditch and seen a tall, fast‑growing tree with compound leaves and a strong smell, you’ve probably met Ailanthus altissima. Also called the Tree of Heaven, this plant is famous for popping up where you don’t want it. Below you’ll find the basics you need to recognize it, understand why it matters, and keep it under control.

How to Identify Ailanthus altissima

The leaves are the first giveaway. They’re feather‑like, with five to seven leaflets that are smooth and glossy. In spring the tree shoots out bright yellow-green flowers that hang in loose clusters, and the bark is smooth, gray‑brown, and often has a faint, peppery odor when you crush a twig. Look for a rapid growth rate—this tree can put on several feet of height in a single season.

Why It Spreads So Fast

Ailanthus altissima is a master colonizer. Its seeds are tiny, wind‑dispersed, and can travel miles. The roots also send out underground shoots called suckers, creating new stems without any seed involved. Because it tolerates poor soil, pollution, and even sidewalk cracks, it often beats native plants in tough urban spots.

Many people think the Tree of Heaven is just a nuisance, but it can have real health impacts. The plant releases a chemical called ailanthone that can suppress the growth of nearby vegetation, lowering biodiversity. Some people report allergic reactions to the pollen or the strong scent, especially those with asthma.

If you’re a gardener, you’ll notice that Ailanthus altissima can quickly overtake flower beds and shrub lines. Its dense canopy shades out smaller plants, and the aggressive root system can damage foundations, sidewalks, and underground pipes. That’s why property owners often have to act fast when they spot a new sprout.

Controlling the tree isn’t impossible, but it does take persistence. The most effective method is a combination of mechanical removal and chemical treatment. Cut the trunk as low as possible, then apply a glyphosate‑based herbicide to the cut surface within a few minutes. This prevents the stump from sending up new shoots.

For smaller suckers, pull them out by hand, making sure to get as much of the root as possible. If you miss any fragments, they can sprout again. Re‑checking the area every few weeks during the growing season helps catch new growth early.

In some regions, local authorities offer assistance with large infestations. They may provide guidance on safe herbicide use or even send crews to remove dangerous trees near power lines or roads. Checking your city’s environmental or public works website can save you time and money.

Finally, remember that while Ailanthus altissima is invasive, it does have a few uses. Its wood can be turned into furniture, and the bark has historically been used in traditional medicine for its bitter properties. If you can safely harvest it, turning a problem into a resource is a win‑win.