Garlon 3 or 4 for buckthorn

[PASS_AUF]

Gentlemen, I would appreciate advice from the pros on this. I'm getting ready to spray chemical at my parents property for buckthorn. I would much prefer to be doing this in the fall and am aware that it is a much better time of year to spray. My dad has been quite sick this year but my mom is at her wits end with everything and she wants it sprayed now. The area in question is along a private roadway, visabiliy becomes a real issue for cars by July. They have had a landscaper "taking care of it" for at least five years. He cuts it once a year and leaves it. This management method has created a solid mass of small shoots and real disruption of the ground floor. 

I'm planning a foliar spray to knock it back this spring and again in the fall. There are mature oaks, maples and shagbark hickory stands in the woods. I've read the oil based garlon 4 is more effective at buckthorn control when used as foliar. Do I risk getting in to the drip lines of desirable trees when mixing 4 with water and surfactant? Or, should I stick to the aqueous based 3?

I will be basal treating the larger buckthorn with garlon 4 and kero throughout the summer to target the females. As well as following up with a fall foliar treatment. Thank you all for the advice! 

[WDH]

Garlon is not soil active so as long as you do not spray the desirable species you will be OK.  Is some spray get on the ground it won't hurt. 

[PASS_AUF]

Garlon is not soil active so as long as you do not spray the desirable species you will be OK.  Is some spray get on the ground it won't hurt.

Thank you for the advice! I can shoot Garlon 4 no problems then? Thank you for your help! 

[RPF2509]

Just be aware that Garlon 4 can volotilize when temperature get above 80 and injure surrounding vegetation. Garlon 3A with crop oil can avoid the volitization issue but usually is not as effective.   Garlon 4 + kerosene is a basal bark application (penetrate through the bark - no need for cut stump) and Garlon 3A  is preferred for cut stump applications (water formula wicked in by the exposed cambium better than oil).  The basal bark treatment is best for young, smooth bark and the cut stump is better for older trees where the bark has become furrowed and corky and the oil formula does not penetrate as well.  Cut stump applications should be done immediately after cutting before the cambium dries and the vessels close. Spring / summer always better for foliar (leaf)  applications as the plant is actively growing and transferring stuff around.  Cut stump/ basal are better later in the year as leaves shut down and the plant transfers nutrients to the roots.  Some species respond best to basal/ cut stump in fall and winter - don't know about buckthorn.  For high visibility areas, a winter basal treatment can avoid the red and dead look a foliar treatment leaves you with.  Come spring all there is to see is dead stems.  I suspect you will need several treatments over a few years  to completely eliminate the buckthorn, if that is your goal.  Chemicals can be a wonderful tool when used against nasty species.

[RPF2509]

Forgot to mention another technique  for the Garlon 3A called hack and squirt.  On larger stems make cuts about every three inches around the trunk, immediately squirt in a little 3A so it fills the cut but does not run out.  On most species this is effective in late summer, fall, winter when the sap is not rising.  Works best on larger diameter trees where you can get a cut big enough to hold the chemical.  ALWAYS read the Label before applying!  If in doubt consult a local expert such as an extension agent.

[RPF2509]

Not sure if you are familiar with some of the terms but a basal bark treatment is sprayed on stems just above ground level about one foot up.  It is most effective on clumps where there are many small stems that can't be hack and squirted and the bark is thin enough for the chemical to penetrate.  Works well when the target species is too tall and you don't want overspray to drift.  It is effective as a dormant application so fall is a good time.  Since your buckthorn has been cut back, I suspect you have many small stems to deal with. Diesel oil, kerosene and crop oil are all effective carriers - the oil helps dissolve protective waxes and lets the chemical penetrate to the cambium and then to the rest of the plant .  What you choose is mostly dependent on how much stink you can tolerate.  Crop oil is the most expensive but has relatively low odor.