I enlisted a few goats and with the help of an electric fence they ate it down in a hurry.

I completely agree that I'd rather dig them out when they're green.  Glyphosate or 2,4-D ALONE won't  get them unless it's early in the season.  So get them early when the foliage is tender, cut them down really low, wait for the new green stuff to start coming out, then hit them with herbicide.  The tender foliage is much more susceptible.


Something like Crossbow is better than 2,4-D or glyphosate alone.  Something that has triclopyr in it will help the 2,4-D perform better. There are lots of generic versions of crossbow.

BE AWARE that triclopyr is notorious for drift.  Read the label and spray in the right conditions. Not dead still with a heavy cloud cover.  Not in wind above whatever the label reads.  Keep your spray droplets BIG cuz a fine mist will drift much worse.  This will avoid collateral damage to stuff you don't want hurt.  Like shade trees or ornamentals.

Imazapyr is used for total vegetation control, so it's going to smoke stuff around the undersirable plant AND it's not only has a long residual (meaning its effects are going to remain in the soil) but it also moves easily THROUGH soil to contaminate adjacent areas and water.  

It is a scorched-earth option, and if you don't care about the residual or the contamination of surrounding groundwater, it will almost certainly kill the target pest.


I would much rather use something that does not have so much potential for collateral damage.

ETA:  OP, if you choose to use Imazapyr, there are generics for a lot less money.

So there is another option...it's Tordon (Active ingredient Picloram).

It's "non-toxic"--to a LOT more things than some of the chems listed by folks here (including me).  It's a "paint-on" herbicide.  Basically cut the plant down, paint this on the cut, and the pest is GOING TO DIE.  

The positive is that you aren't going to hit stuff around it, because it's so targeted (like a basal bark spray--both treating cut surfaces and basal spray are excellent choices) EXCEPT...

And this is the big "except"--if you've got a big tree right next to your pest plant, and the roots of the rose have even *thought about* root graftting with the tree, you're going to kill the big tree.   Tordon is capable of killing plants with roots that are close to the target.

This is not quite as big hairy scary as it sounds, but you need to be aware of it.

I use Tordon a lot. I just use it really carefully.   And I don't put it on targets that are within the main dripline of a tree I care about.

Anything that you "spray" on the entire plant, is going to be more likely to leach into ground water, run off, and kill non-target pests around the rose.

Painting it on the cut is going to to keep it WITHIN the target plant (or within the roots it crosses to, per my caution above) and out of the soil.  You also use a smaller quantity of the pesticide, and it is not dispersed in air.  Small drops, dispersed all over the place, are the worst option for pesticides *usually*.

I missed this.  I suggest tordon as an alternative without realizing you had done so already.