Plant Profile: Thistles

Thistles are tough, prickly weeds that can be difficult to remove from your garden. These weeds can quickly take over and spread, choking out other plants and creating an eyesore in your yard. There are several effective methods for removing thistle from your garden thankfully. In this blog, we’ll explore some of the best ways to remove thistle and keep your garden healthy and beautiful.

1. Hand pulling: One of the most effective ways to remove thistle from your garden is to simply pull it out by hand. Thistles have long taproots that can make them difficult to remove, but with a little patience and persistence, you can usually get them out. Make sure to wear gloves to protect your hands from the prickly leaves, and try to pull the entire root system out to prevent the thistle from regrowing. Pulling them out will be easier after a rain storm or if the weather has been very dry.
2. Cutting: If you have a large number of thistles in your garden, you can use a pair of pruning shears or a weed whacker to cut them down to the ground. This will prevent them from flowering and producing seeds, which can help prevent the spread of the thistle. However, cutting the thistle alone may not be enough to completely eliminate it from your garden. If you decide to cut them out, I would follow it up with tip #4 and #3 below in that order.
3. Smothering: Another effective method for removing thistle is to smother it with a layer of mulch or a thick piece of cardboard, or even garbage bags. This will prevent sunlight from reaching the thistle and can cause it to die off over time. This method does take a few weeks, and if you’re using garbage bags make sure to remove them so the plastic does not stay in the garden bed. Make sure to completely cover the thistle with the mulch or cardboard to ensure that it is fully smothered.
4. Herbicides: If you have a particularly stubborn thistle problem, you may need to use an herbicide to eliminate it. Look for an herbicide that is specifically designed to target thistles, and make sure to follow the instructions carefully. Keep in mind that herbicides can be harmful to other plants and animals, so use them with caution and avoid spraying them on windy days.
5. Prevention: The best way to deal with thistle is to prevent it from taking hold in the first place. Make sure to keep your garden well-mulched and weed-free, and avoid planting invasive species that can create a hospitable environment for thistle to grow. Regularly inspect your garden for signs of thistle and remove any plants as soon as you spot them. Also, this is speaking purely from anecdotal experience, but the quality of mulch will play a major role in thistle prevention. Bagged mulch from big box stores we have noticed tend to be magnets for thistle. Low quality mulch companies who leave weed seeds in their mulch also play a part.
6. Complete Removal: Sadly, we have seen some gardens so utterly infested with thistle that we have to remove all the soil and start over again. Thistle can root so deep in a landscape that only digging it out will stop it from ever coming back.

There is no weed more despised by landscapers than thistle. Removing thistle from your garden can be a challenging task, but with the right approach, it can be done. Hand pulling, cutting, smothering, herbicides, prevention and complete removal are all effective methods for removing thistle and keeping your garden healthy and beautiful. By taking steps to eliminate thistle from your garden, you can help promote the growth of other plants and create a more attractive and enjoyable outdoor space. Just remember this: ACT EARLY! If you let them grow to seed, they will multiply by the dozens and make the problem much worse.