[hollow_hunter]

I would like to spray these suckers before the hunting season, but I want to make sure the spray works its way into the roots of the tree. Do you think its ok to spray now, or should I wait till September?

 

[Guest]

You can drill into the trunk, on a downward angle, and pour some Roundup in the holes and it will kill the tree.

Not sure how spraying the foliage would work. I'd mix the Roundup a tad stronger than normal.

 

[hollow_hunter]

I'm not going to spray the foliage. I wanted to cut the bark and apply the Roundup. But I like your idea better. Drill it and let them soak the poison.

 

[Borden811]

Fall will work best, as it will kill the entire root system. Spraying( orhack/squirt) now will kill the tree and most of the roots. You might have to sparay again for a couple of years to get all the root sprouts if you don't kill them all the first year or two. If you can get some Garlon 4, and mix it 25%-75%(one quart to a gallon) with basal oil(or diesel fuel),it will kill the heck out of them. All you have to do is spray or paint it on the bark from the soil line to about 2 feet high, and it will absorb through the bark, and kill the tree. The roundup will work too, but as stated, it will work much better if you cut or drill into the tree. You don't have to cut or drill in very far though. The only part of the tree that will take up the herbicide is the cambium layer, directly inder the bark. The rest of the trunk is just dead wood. The roundup will take longer however, and might not be as effective at getting the entire root system the first application.

 

[Timberbeast]

Fall will work best, as it will kill the entire root system. Spraying( orhack/squirt) now will kill the tree and most of the roots. You might have to sparay again for a couple of years to get all the root sprouts if you don't kill them all the first year or two. If you can get some Garlon 4, and mix it 25%-75%(one quart to a gallon) with basal oil(or diesel fuel),it will kill the heck out of them. All you have to do is spray or paint it on the bark from the soil line to about 2 feet high, and it will absorb through the bark, and kill the tree. The roundup will work too, but as stated, it will work much better if you cut or drill into the tree. You don't have to cut or drill in very far though. The only part of the tree that will take up the herbicide is the cambium layer, directly inder the bark. The rest of the trunk is just dead wood. The roundup will take longer however, and might not be as effective at getting the entire root system the first application.

Borden is correct.
Garlon is the best herbicide for Ailanthus. Depending on where you live you should treat it late in the summer/early fall. At that time the Ailanthus will be pulling nutrients down to the root system and at the same time, hopefully, some herbicide.
If you want to use glyphosate (Round Up) you MUST treat it in the late summer/early fall. Hack-n-squirt will work very well, but the timing is important. If the Ailanthus has any size you can just use the diameter plus one method. Measure the diameter of the tree and just add one. That is how many "hacks" you want to use. Make sure you leave some living tissue between each hack. That will allow the tree to still pull nutrients down to the roots along with some herbicide.
Good luck!