To contain these trees you will need to be able to put in a thick barrier 1/2" (1.5cm)thick will hold the roots, then you have to dig up all the roots beyond that point since they will sucker as many have already mentioned. If you feed them, they will have the vigor to break through any barrier except for stainless steel eventually.
Mark Richards wrote:Hi Everybody!
I'm working on an urban gardening project in Budapest, Hungary. We're converting a gravel lot to community garden with containers for now, but we're planning to do some major work in the fall after we've had a season feeling out the conditions. We've got a wall and a row of alianthus trees protecting us from a street, pollution and wind, as well as helping reduce noise. It's a tightly packed row of trees, about 15 years old, maybe younger because they grow fast, 4-6 inches in diameter in front of the wall. I've discovered they eat sulfur dioxide from the air and take up mercury from the soil. Nice services for the city. We'd like to keep them for all those services, if we can. Replacing them would be costly. So my question is, how?
The downsides are that they smell like rancid peanut butter if damaged. They also produce an allelopath in the soil, and their roots are reputed to break walls and into sewer mains. They invaded the bombed cities of europe after the WWII.
We're considering a few options before cutting:
1) feeding them - maybe building an embedded raised bed along the wall, while cutting back the roots that reach out into the garden space, and filling above ground level with their somewhat annoying leaf litter over time, along with some compost. The idea being to give them food and they won't need to invade our veg beds. Hmm...?
2) coppice or pollard them - maybe every other tree could be coppiced to head height. Could this decrease the competition between them, for root space and sun? They tend to send out numerous suckers if cut down- this we want to avoid. We could coppice them all to wall height.
3) a transition trench - maybe we could cut a trench, fill it with the gravel we have, for a path along the row, and try to keep their roots cut back each year. It doesn't seem to stop them, but in combination with 1)feeding, they might be deterred.
4) a companion hedgerow - with a living hedge between them and our garden, we would have them up in the low canopy story and some kind of hedge story might insulate our soil from the allelopathy and make the space wonderfully insulated from the city. But what lives near these trees?
I've hardly any experience with these trees, or trees in general, so it's all theory to me at this point.
Anybody have any recommendations? or alternatives? Who anybody in their right mind try such an endeavor?
Thanks for any feedback,