Weed Control for Evergreen Trees

Weed prevention is very important to the success of your tree planting project. Weeds block the sunlight that your trees use to make food, and they consume water and nutrients from the soil. Below are some options for weed prevention.

Herbicides

Roundup is a popular, effective and widely available herbicide, but it kills EVERYTHING, so use with caution. To make a spray barrier, you can cut the bottom off a 2 liter [or cut a length of PVC pipe or carpet tube], slide that over each tree until it is flush with the ground, and then carefully spray around the 2 liter...but be careful that the Roundup doesn't drip off the 2 liter and onto the tree as you remove it. It is also important to avoid creating a fine mist which can blow onto the trees by the wind. Set the sprayer to produce droplets which fall to the ground.

Preen is a pre-emergent weedkiller, meaning it does not kill germinated/growing plants. Apply Preen to bare soil around each tree and then cover the Preen with mulch or sawdust to create an effective barrier against weeds and a good insulator against moisture loss. Preen is widely available at garden centers and big box stores.

A product new to us is Hi-Yield Grass Killer, which can be sprayed over most evergreen species without harm, while killing most grassy weeds. We have no experience with this product, but it sure seems to be a promising way to keep your young trees from getting overcrowded by tall grasses [download Hi-Yield Grass Killer PDF].

There are commercial herbicides which can be directly applied to evergreens without hurting them, but you may need a license to buy them. Goal is quite popular in the wholesale industry, and in our opinion it has revolutionized the nursery industry:
http://www.dowagro.com/ivm/forestry/prod/goal2xl.htm

Paint Thinner

Believe it or not, you can spray weeds with paint thinner in the late morning of a hot/dry day, and most weeds will be dead by evening. Thinner strips the protective wax off the leaves of the weeds, resulting in rapid dehydration of the weeds while having little or no effect on the trees [I don't know why]. Try spraying very closely around [but not directly on] a few trees before noon, and check the results that evening or the next day. When I was participating in spring sports in high school and college, the weeds always got ahead of me. I sprayed paint thinner directly onto my own seedling and transplant beds, killing 90% of the weeds while losing just a small percentage of the trees [thus saving myself many, many hours of Spring weeding, time which I did not have]. However, I don't recommend spraying thinner directly on your own trees due to the risk. For extra safety, you can use the 2 liter trick [as described above] with paint thinner too. And be sure to finish your cigarette first!

Please keep in mind that spraying herbicides or thinner is not environmentally friendly, but it can get you through a tough spot. On the other hand, a lawnmower coughs out the equivalent amount of pollution as ELEVEN late model cars...hmmmmmmmm. Take a look at the weed prevention methods below.

The Safe, Environmentally Friendly, Time Tested Method

We don't endorse chemical applications for obvious reasons. Nothing is safer or more environmentally friendly than a sharp hoe. It's actually quite easy and effective once you [1] get the hang of it and [2] get ahead of the weeds. My grandfather walked casually through his many beds of trees uprooting weeds, and he never bent over or strained his back. He weeded regularly to keep the weeds from getting too big to quickly uproot with a quick flick of the hoe. Funny thing is, he always worked right-handed, and wore down his favorite hoe far more on one side than on the other. He also lived to be 85, and perhaps one of his secrets to longevity was working smarter [not harder] and avoiding chemicals whenever possible.