Don’t let the white and purple flowers fool you. Thistles are actually a type of weed that grow very quickly and can be extremely difficult to control. Just ask our Home Depot Community member, Flower, who stumbled across thistle in her garden. After trying (and failing!) to eliminate this pesky weed on her own, she decided to take her problem to The Home Depot Forums, where Forums associate GardenGail offered much needed help:
Flower: I have noticed that some thistle has sprung up in my planting beds where I have numerous day lilies and hydrangea. Is there some way to eliminate the thistle without killing the perennials? I have tried a wide variety of homemade methods and they do not work. I know Roundup would kill the thistle weed, but it would also kill everything else. Does anyone who has ever had this problem know of a solution?
GardenGail: Hello Flower. Unfortunately, thistle is a hard weed to kill because of its root system and the seeds will root anywhere, so don’t let it go to seed. You can cut down the weed a bit so it is easier to spray, allow it to re-grow a bit, and water it (Yes, water it. The faster it grows the faster it dies!).
So how exactly will Flower be able to kill this problem weed? And what about her Roundup question? GardenGail goes on to explain …
GardenGail: You will probably have to use Roundup. There is a great new foam spray version, so you can tell what you have hit. Use a large piece of cardboard to protect the area you don’t want to spray. Once the spray hits the ground it does not work anymore. Re-spray the area a week later, if the weed is not crispy and easy to dig up, re-spray again. Dig gently to loosen the weed and try to get as much of the root as possible, then remove it.
If you have any other garden-related questions for GardenGail, or any of our other expert associates, they’ll be happy to help! You can also take a look at our Garden Center on homedepot.com for garden supplies and inspiration.