Normally I reccomend using Oust and roundup the fall before a tree planting and then follow up herbicide control after planting. I didn't get cost share approval until too late and then I had some unusal circumstances that had me unsure exactly where rows would be this spring.
One area my son and I cleared of thorn trees and blackberry brambles this spring before planting and the area was wet and uneven. When we planted, I just headed the tractor and planter wherever I could get between stumps, girdled trees and wet areas.
Long story short, I'm spraying
after trees budded out which requires a little care not to spray the tree leaves themselves. Surflan is safe over the top but Oust can damage or even kill new seedlings when sprayed over the top of trees that have leafed out.
Oak seedlings can tolerate Oust but most shrubs cannot, conifers can handle atrazine and even roundup if they have not started growing (mine have
)
At any rate I have mutiple situations requiring different (or allowing) herbicide combinations.
I've been band spraying everything with my 3 gallon backpack sprayer and spraying an atrazine/roundup combo around (not over top) all the red cedar seedlings.
Surflan is a pre-emergent herbcide but Oust is both pre-and post:
DuPont™ Oust<SUP>® is a soil residual herbicide with some knockdown action. It controls susceptible weeds through both post-emergence and pre-emergence (residual) action. DuPont™ Oust® may be applied pre-emergence or post-emergence to the weeds; best results are obtained if application is made before or during the early stages of weed growth. </SUP>
<SUP>
Adequate soil moisture is required for DuPont™ Oust® to be activated so it can provide optimum weed control. Under limited rainfall conditions, DuPont™ Oust® may not provide satisfactory control of hard-to-kill annuals and perennial weeds.
The higher use rates give longer term residual control. The degree of control and duration of effect will vary with the rate of application, soil texture, organic matter content, soil pH, rainfall and other environmental conditions.
When applied as a spray, OUST® XP is absorbed by both
the roots and foliage of plants, rapidly inhibiting the growth
of susceptible weeds.
</SUP>
I used Surflan and select 2-EC on some newly planted oaks but in the area we cleared and the oaks have had plenty of rain to settle soil around the roots I used Surflan and Oust XP at 1 quart and oneounce in 3 gallons of water.
I tried to avoid any contact with the leaves but of course managed to hit a 1/2 dozen out of perhaps a thousand seedlings, so we'll see if they survive or not.
I used no surfactant:
If a surfactant is used with OUST® XP, allowing the spray
to contact tree foliage may injure or kill trees. The user
assumes all responsibility for tree injury if a surfactant is
used with OUST® XP treatments applied after planting.
Obviously Oust is pretty potent stuff which is also why it works so well.
My hope is that it will nuke the blackberries and goldenrod coming up in that planting and then provide residual control.
Oust XP Label
Oust is in a granular form that requires careful measuring with a this hand deal that is a little like measuring black powder...
I measured one ounce, twist it shut and remove the measuing canister from the bottle.
The Surflan has a yellow dye in it which really helped to know where I sprayed...
Before....
After...
Notice there is no grass in this situation, so I didn't add Select (clethodim)