Tree of Heaven - Ailanthus altissima

The Tree of Heaven (Ailanthus altissima) is a Chinese tree that I have seen featured in more than one botanical garden in Spain (in Madrid and in Malaga) but it is also, in my opinion, the most invasive and troublesome of all the non-native trees in Spain. The Tree of Heaven is not an ugly tree, in fact it has some interesting ornamental properties when in flower and when its samaras are forming. It is also a very prolific and fast growing "weed" that is fast propagating itself in virtually all parts of Spain.

One of its favorite places to spontaneously sprout is along the sides of roads and freeways. I think that this is due to the fact that the winged seeds (Samaras) often fall onto parked cars and are then transported along until they fly off the top of the car and end up along the side of the road where they then do what they seem to due best - grow!

This is one of the tree species featured in the "Around the World In 80 Trees" exhibit in the "Jardin Botanico-Hisorico" of Malaga. If you take a closer look and the areas around the tree you will discover that this tree species is making a run and taking over the garden. It seems to like the climate a great deal.
The image below is of a thicket of Ailanthus altissima along the side of a road in Southern Spain.


  1. I agree on the invasive and troublesome comment, these trees seem to pop up over night in the most unlikely places. They are all over the Eastern United States in and around the cities.

  2. Dan, are you still interested in hosting the next Festival of the Trees? Dave and I have been trying to reach you to finalize some details. Send me an email and let me know how things stand, okay?

    editor (at) roundrockjournal (dot) com

  3. Hello,
    altough it´s an invasive tree, it a lot of places in Spain, is the only tree that growsn in dry areas, and so it my case it´s beneficial, as many of these places wouldn´t have trees because it´s too dry or native trees have been cut down or burnt in forest fires, or killed by droght.
    Also it´s an attractive trees, that when flowers looks tropical, so it adds a bit of warmth in hot spain!

  4. Does anyone have advice on how to kill these trees?
    We had four of them removed from our yard and now have offspring popping up from all of the roots, really a nightmare.

  5. They are disgusting! I live in New Jersey and they take over everything. They grow so thick in abandoned fields, along roads and around houses that you can't even walk through them. I've even seen them growing on roofs of houses.

  6. West Coast... Riverside, CA (with extreme hot/dry and cold weather) have them all over the place - guess seeds are airborne and pop they grow. My aunt's neighbor had the trees and neighbors have just been pulling (dead-heading) the shoots from the yard (all over) when they show up. Then, one day we decided to help with the garden and tried to dig the roots out and, oh my, omg! May have to dig the whole property (even inside the house wherever there is a crack - like openings for sewers)as it is really ALL over. Can see cracks on cemented driveway and pathways - house has not risen though (not yet).
    Yes, they have even invaded the sewers - plumbers say the whole neighborhood had serious plumbing issues due to the roots clogging the sewer pipes.
    Positive side? ---could be good reforestation trees... maybe we can gather the seeds, pack them inside cheesecloth/old socks/papertowels with wet soil, and toss them on roadside or wherever place needs trees and we may solve some environmental problems (hopefully not to create new ones)... wonder if the flowers and seeds can create fire problems? --- oh no!
    Ahhhh, life's eternal challenges and counterbalances... how/where/why did it get its name - TREE OF HEAVEN?

  7. Big problem in parts of Australia too! In our river community we are actively seeking to rid our area of it.
    To get rid of it and control it, using "round-up" or Glyphosate is the chemical name.
    The tree must have leaves, which would be in the warmer months, not when dormant. For any plants with a stem up to the thickness of a broom stick, we scrape with a chisel down both sides for about 2-3 inches as close to the bottom as possible and then apply straight, undiluted Glyphosate directly to the wound. This must be done within about 30 seconds of chiseling. Do not cut the tree down but allow it to die intact.
    For larger specimens, go around the base of the tree as low down as possible, with a chisel and chisel a deep notch into the tree & apply undiluted Glyphosate into it, as above. Go around the entire base leaving a space the width of the chisel between each notch. If the tree has more than one trunk or has copiced, you must do each one & treat any offshoots from the roots. It sounds a lot but is actually one of the easier ones to treat if done properly. If you have a mass infestation of very small, up to 12 inches, and nothing else much growing in between you can spray with 10% Glyphoste diluted with water. But you will kill other species that get any over spray. So you have to weigh it up whether the other species are important enough to preserve. For instance in a riverbank where native re-growth is desired, as opposed to a paddock with other weeds & grass between.
    I had a massive problem with them in my paddock, after 1st treatment and death of all mature seed trees, a monoculture covering about 1 acre, I got about 400 seedlings came up the next season. I sprayed these due to the numbers and there was little else growing to be concerned about at that point. The next season, about 30-40 came up & I used the chisel scrape method above. The next season just 3-4 popped up. Every few years I get an odd one. In my riverbank where I had a big problem with privet(same chisel method to kill, small ones hand pulled) & less Tree of H & a healthy mix of good natives. Here I used the 2 chisel methods above and selectively poisoned them.
    Once they were all well and truly dead I chainsawed & burnt the larger trees and just left the smaller ones.
    2 things to note: The leaves when brushed against have an odour and make some people feel unwell & the smoke from burnt ones, also. Occasionally a large tree, particularly one that has copiced may require treating again.