The horehound weed is known as Marrubium vulgare, and is native to Europe, the Middle East and North Africa. The horehound weed is a bushy perennial plant with a defining white tip. The weed lives upon poor soil and grows in areas that contain animal waste. It most commonly affects sheep pastures and the plant's burrs can damage the growth of sheep fleece. The horehound weed also grows near gardens where there is animal or organic waste, dead leaves and rotten fruit. It's important to remove these weeds in order to protect the soil of your garden.
Mark all of the areas where the horehound weed has been appearing in the summer. You can use spray paint or tiny flags to mark these locations. Keep these locations marked until December when you can use a solution to prevent the weeds from growing again in spring.
Wait until winter to try to kill the horehound weeds. Snow or cold temperature will not affect the solution to the soil, but don't spray the solution in below zero weather. Prepare the solution at the end of December or the beginning of January. This will assure that the solution is fresh and active to kill the weeds before they can start to grow.
Pour 1 gallon of cool water into a large bucket, and then add 12 oz. of white vinegar. Stir the mixture with a wooden spoon or paint stick. Add 2 oz. of orange essential oil and 1 tsp. of liquid dish detergent to the mixture and stir well.
Pour the mixture into a garden sprayer. Do not overfill the sprayer. If you don't have a garden sprayer, use a water bottle, but you will need to continually refill it.
Spray the solution all around the area where the horehound weed has been growing. Soak the area well and then dispose of any leftover solution. The orange essential oil and vinegar are the key ingredients that specifically kill horehound weeds. Also, this solution is safe for your soil and lawn. When spring comes, the grass will grow back without any sign of horehound weeds.