Problems With Thistle

Problems With Thistle

Sam --- 

Nick! Thanks for spending time with me at Green Fair on The Fox about my Thistle issue. Can you refresh my memory about what my treatment options are for this?


Natural Communities ---

Sam, excellent to see you again!!

The weed appears to be Canadian thistle. There are several methods that can be implemented, but one should always consider the approach with the least environmental impacts first.  For natural areas I will discuss several ideas from the greenest to the least environmentally friendly.


Prevention is always ground zero, having a good crop of native plants such as Asclepias syriaca (Common Milkweed), Echinacea purpurea (Purple Coneflower), Ratibida pinnata (Yellow Coneflower), and native grasses like  Andropogon scoparius (Little Bluestem) prevents weeds from growing.

First is cultural/ manual treatments:

Hand pulling is the best option in a small scale project, pullout as much root as possible, this is best done when the soil is wet just after a rain. Second is weed whacking to prevent seed production and reducing root energy reserves of the weed. The cutting of the weeds, whicle leaving the native plants will eventually shift the planting to native dominance.  These ways will take the longest but are the greenest way possible. If you continue to pull/cut and have the native competition it will eventually disappear. The native competition is the most critical step!!!!!

Second is Chemical Treatment:

Horticultural grade vinegar, or a natural herbicide like Phydura is the greenest option in chemical control. These are natural but not without their issues, but much greener than most chemical treatments. They are non-selective (they will kill anything they touch) so watch out for desirable plants. Least green of all is synthetic herbicides. Triclopyr amine (i.e. Garlon 3a) products are systemic (meaning they kill the roots) and select for only broad-leaf plants (they kill only flowering plants for the most part and not grasses). Garlon 3a is mostly a commercial product so you may want to investigate Weed-B-Gone or similar, which is a mixture of several broad-leaf herbicides. Use these as labeled!!!!!


Again, prevention is always ground zero.  Plant thick stands of native weeds at the onset and it will prevent many weed problems.  After any of these weed treatments replant with native plants to regain that plant competition.  If the weeds cannot get at the water, light, or nutrients they cannot establish.


A note on burning and weed control. When applied correctly controlled burning can be your best bet to control woody invasive species, particularly on a large scale. Controlled burning can have minimal effects over sustained practice on herbaceous weeds.  Make sure you always have the proper training, safety gear, and permits to implement!!!!



Well Sam, I hope that helps!!!  Happy weeding!!!




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