We are getting ready to spray out treeless front 4 1/2 acres so not worried about what we are using but I have a lot of yard and pasture (15 acres) that is moderately treed than I need to get a handle on. I am using a sprayer setup on my tractor so there will be over spray. Luckily I can get off the tractor and use the hand wand if needed but something that would be safe on trees would be nice.
You need the right droplet size for drift control, the right application rate, and to never ever ever spray on windy days. Tress are sensitive to any and everything. But adult trees should be able to handle it.
I even spray around my baby trees, but again, drift control and correct rates.
2-4-D. It is safe for horses.
I have read on different forums of people leaving their horses back on the pasture right after spraying but I’m not that brave, I waited 24 hours. We have ~24 acres cross fenced so while one section was drying for a day, the horses grazed in the other sections.
2-4-d is very livestock safe and great for killing various types of broad leaf but it won’t kill weed grasses such as Dallis grass. You would have to put an all-kill down and there goes the entire pasture killed down to the dirt.
Trees aren’t as susceptible to herbicide because of their size and deep root system, plus that you tend to not spray it directly onto their leaves, since their leaves are way up in the air. In the past I’ve had to use herbicide to kill bushes (rhododendrons) that couldn’t be cut down and you actually have to drill a hole into them and dump the herbicide into the hole to kill them.
So, just don’t spray the trees directly for a long time and it should be fine.
This is true, and not true. The herbicides are no joke - even in residential areas, I still get damage on my plants from the likes of TruGreen etc. Some of these herbicides are taken up by the roots, like dicamba, and I am VERY careful with that particular herbicide. Any tree is susceptible to damage, some more than others.
Herbicide uptake by tree roots is something we are only just beginning to understand. It is most common in trees in lawns/ROWs that are routinely sprayed with broadleaf/non selective herbicides. Dicamba (very commonly used for dandelions), Picloran (GrazeOn), and Triclopyr are all known to cause significant damage via root uptake. Picloran is something trees are very sensitive to.
You also need to consider volatization of the herbicides. I was only worried about drift due to wind and not temperature until an incident this spring. However, it was unexpectedly hotter that afternoon than I anticipated and despite spraying in the early morning to avoid drift, I was still in the 24 hour window for it to become airborne due to heat. Which it did. It caused minor but definite drift damage.
In my view, herbicides of any sort need to be used with caution and as minimally as possible. I think there is a lot of unspecified decline of lawn trees due to repeated herbicide damage over years.
This is a decent article that discusses it but I think is actually not quite as emphatic as probably it should be:
All that dicamba damage is due to drift, not root uptake. You can do a lot of damage to trees if you spray - purposefully or not - enough of the foliage during the growing season.
@CindyCRNA what are you spraying for? Are there large numbers of trees IN the pasture area, or just around the edges? Your county extension agency is likely your best bet, as they should have enough experience spraying for weeds in areas that have more than just the weeds they are targeting that might also be susceptible to the chemical(s)
The pictures agreed, but the article details the soil issues from it.
Dicamba has been specifically called out by a number of agencies as being very transmissible via root uptake. It is designed to be transmissible by roots, that is why it is so effective! Is it going to kill a tree in one go if you spray the lawn/pasture with it? Probably not, but repeated applications during the active root/leaf growth periods will cause damage.
I use herbicides, I will continue to use herbicides, but we desperately need to have more careful consideration of them. Especially for the lawn care companies (a personal soapbox of mine)