Spraying crossbow

Looking for opinions on best method to spray crossbow. Got saplings popping and was wondering should I just spray or now then spray. Just looking for what will give best results.

Basal spray or foliar spray?

I've used crossbow (mixed with on oil) for basal spray on the root collar with success at anytime of the yr (winter included). But it doesn't work well with honey locus. It tends to sucker around the original tree when I spray it. I've read that Remedy Ultra won't let them sucker like that but haven't tried it yet.
Here is a decent article if it helps any:
Are you using the right cut stump herbicide? | Missouri Department of Conservation