remove poke weed
Pokeweed (Phytolacca americana) is an herbaceous perennial weed that regrows each year from a large taproot. It reproduces via seeds within purple to black berries produced in the late summer/early fall and can be spread by birds and other animals.
To provide the best control recommendation I need to know where the pokeweed is located and what desirable plants are nearby. Is this a single plant or a larger infestation? Please respond to this post with more detail or email me directly (firstname.lastname@example.org) so that I can best help.
It is large infestation that appeared after we harvested red pine trees. It is still located amongst pine trees. There are no desirable plants surrounding area that are in peril.
Options for control include tillage and herbicides. Tillage may not be feasible given the description of your area. In a non-crop, bareground areas you can use the following herbicides.
Glyphosate (active ingredient in Roundup Weed and Grass Killer Super Concentrate, among others) is a broad-spectrum herbicide that will kill any grass or broadleaf plant with which it contacts foliage, exposed roots, or damaged bark. For pokeweed control, it can be sprayed on the foliage or applied via the cut-stump method outlined on the label. The cut stump method would likely be the safest when working close to the existing trees to avoid drift, though so long as the bark is intact and roots not exposed your primary concern with drift would be foliar contact. The advantage of using glyphosate is that you can replant the area usually within a day of treatment if desired.
2,4-D and triclopyr (a.i.s in Crossbow) are effective against broadleaf species, such as pokeweed, that can be applied to the foliage. This herbicide will not harm grass species, but it may affect plans to replant the area with broadleaf plants, shrubs, and trees (consult the label for details). These herbicides are also more prone to movement through volatility, so this product may be riskier than glyphosate depending on the proximity to the desired trees.
Herbicide applications are most effective for control of perennials in the fall when plants are actively translocating resources to the root system; however, they can be applied any time the plants are actively growing.
With any herbicide application, read and follow all labeled instructions. Also, be cautious and aware of drift as it may harm nearby desirable plants.
The area will need to be monitored to access the need for retreatment of current plants and any new emergence from seed. Planting competitive plants in this area and certain cultural practices, such as regular tillage or mowing) can help prevent re-infestation.
Hi Erin, Thanks for your response. I am a little confused re tillling the area as I was always under the impression that tilling anything like an invasive weed, etc would tend to distribute the roots and seeds more.
Tilling can be effective depending on the weed. Pokeweed reemerges each year from the same taproot, but does not reproduce vegetatively through underground stems (rhizomes), tubers, or above ground stems (stolons), therefore tillage is effective. This is also why pokeweed is not a major weed in large agricultural settings that use tillage, but more often found in sites with less soil disturbance. Weeds that reproduce vegetatively are more likely to be spread through one tillage event (e.g. quackgrass, Canada thistle, etc.)
Seed may be moved around via tillage, that is true, but one tillage pass will likely dilute the population in the upper 1" of soil and bury some below the depth at which successful germination or emergence is possible.
I wasn't sure if tillage is an option in your case given the tree roots.