How to Cut & Spray Weeds & Thistles
- 1). Wait until the thistle plants develop tall stalks but have not yet produced pink flower blooms. Treating the thistle at this time prevents it from seeding. Most other weed seeds will also be just about to develop flowers as well. Thistles are harder to control than other weeds, so plan to mow when it is ready to flower.
- 2). Install a grass catcher bag onto a lawnmower using the mower's instruction manual. Set the blade depth on the mower to between 2 and 3 inches, and mow the entire area of thistles and weeds to cut them off.
- 3). Remove the grass catcher, and dump the contents into a trash bag. Tie the trash bag up tightly, and place it into the trash for disposal. Do not dump the clippings elsewhere in the yard because they contain weed and thistle seeds that can sprout.
- 4). Fill a garden sprayer with an herbicide containing 2,4-D as the main ingredient. Use 1 lb. of herbicide for every acre of land that you are treating, and dilute it with water as instructed on the bottle.
- 5). Spray all of the thistles and other weeds in the area until they are saturated and the leaves and stems are completely covered in the herbicide.
- 6). Wait one week and examine the thistles and weeds in the area for signs of growth. If needed, apply another application of herbicide to the weeds.
Source...