Spraying Glyphosate and Pine Trees

[RobD70]

I sprayed a homeowners lawn with Durango, a glyphosate weed killer to kill off the entire lawn for a complete renovation, I plan to use my Kubota L3800 and power rake to do the work. That was about 2 weeds ago. I stopped over today to use the hand sprayer to hit some green areas I missed or needed a little extra shot. It was a little breezy the day the grass was sprayed, not to bad, but where the home is, the wind swirls some. He has a couple rows of pine trees that are on average about 5 feet tall or so and I am sure overspray got on them. When over today, they showed no signs at all of discoloring yet. My question is this, if enough overspray got on them, how long does it take for it to start to show? I know it takes a fair amount to kill a tree of this size, but Im guessing some needles would turn color at least for this year. I have read in some spots that say it wont kill pine trees, and have read in other spots where it can. Im hopinh it dont hurt them.

Thanks

Rob

 

[Deere Dude]

I sprayed some around 3-5' pines to kill weeds. Sure enough, the bottom branches turned purdy brown. But about two months later I can't see any effect on them. I wouldn't worry about it. I will stay farther away from them next time though.

 

[LindenBruce]

That's why I spray in the early morning to avoid the breeze carrying to my pine trees. I hope they survive. B.

 

[TCowner]

I spray Roundup around my spruce trees every 2-3 weeks to keep the weeds under control. I have a 25 gallon three point hitch sprayer that I use with the Deere 1026R. It doesn't have a boom attachment so I just use the wand. I try to limit the over spray but I get some on the lower branches from time to time and it doesn't to do much harm. I notice a few brown needles once in while but actually very few. It seems like I might be a little more of a problem in the spring when the new growth has started and the needles are soft and probably absorb more of the herbicide.

I wouldn't recommend dousing the tree in the chemical but if one is careful a little over spray will cause minimal damage in my opinion.

 

[BreezyacresNY]

We used RoundUp to release coniferous trees (spruce, fir, larch, pine) on thousands of acres in the fall after the buds had hardened. Mid Sept- Mid Oct in the NE the trees can be directly sprayed with no side effects. Careful, Ornamental trees vary in sensitivity.

Not being able to wait till the fall you should avoid using any additional surfactants in the mix which can increase penetration in the coating on the needles; also keep the droplets fairly large using larger nozzles and lower pump pressure if it is adjustable. The fines from spraying can travel relatively far. There is "drift retardant" available which will reduce fines at an additional cost.

Lastly glyphosate works in the roots over several weeks depending on the plant physiology, or how well the plant processes are doing, drought or dormancy factors. Glyphosate effects should be fairly obvious after two weeks of normal conditions.

Hope this is what you were looking for,

 

[Deadman]

Once they harden off, I hear you can spray them and it doesn't hurt them! I never tried it tho!

 

[rd_macgregor]

I'd also heard that spruce trees aren't very susceptible to glyphosate. On the flip side, then, what is a good herbicide to use if you DO want to kill spruce trees? Here, they are an invasive weed that keeps trying to take over my fields. If you mow them when they are really small, you just end up creating your own mini-Krumholz field, but I don't want to wait for them to get big enough so they will die when I cut them...so herbicide seems like a good choice.

 

[AaronS]

I'd also heard that spruce trees aren't very susceptible to glyphosate. On the flip side, then, what is a good herbicide to use if you DO want to kill spruce trees? Here, they are an invasive weed that keeps trying to take over my fields. If you mow them when they are really small, you just end up creating your own mini-Krumholz field, but I don't want to wait for them to get big enough so they will die when I cut them...so herbicide seems like a good choice.

I'd think Crossbow or any generic "brush killer" would work. If they're particularly pesky, look into Tordon Rtu.

 

[rd_macgregor]

I'd think Crossbow or any generic "brush killer" would work. If they're particularly pesky, look into Tordon Rtu.

Will any of these kill the trees but not the grass or clover or are they all broad-spectrum?

 

[AaronS]

They will kill clover and other broadleaves, but not grass.

 

[rd_macgregor]

Thanks, AaronS. Unless I come across a forestry mulcher, I'll likely have to resort to herbicide or just let the trees continue their encroachment into the fields.

 

[RalphVa]

Get an empty 2 liter drink container and cut it horizontally in the middle. Slip the part with the pouring spout/screwed end onto the sprayer head of your glyphosate sprayer (may have to unscrew the spray tip, slip it on and rescrew the sprayer tip). You can just cover a weed or area you want to spray with the drink container open end, and it won't go anywhere.

Ralph