Controlling Motherwort and Tree of Heaven


Hi, my new neighbour is a herbalist and her motherwort has jumped over to my yard. How can I control it without using herbicides that might make it into her yard? On the same note, I have (and dislike) a tree of heaven in my yard, which the previous owner allowed to run wild. How do I eradicate these? Do I need to remove all the topsoil? Spend years hand-pulling? Just put black plastic over the yard and bake everything?

Thanks so much! (I love this service).


You are correct,  Tree of Heaven, Ailanthus altissima, is a very invasive plantand requires patience and vigilance to eradicate it from your property.

For successful removal of Ailanthus, you must kill the roots and prevent additional sprouting. Your best option to get rid of this pest is to dig up or pull the young seedlings, as you have been doing.  Be sure to remove the entire plant – this includes all roots and fragments, as you don’t want the plant to regrow.  It will take persistence to remove root suckers and the thriving network of lateral roots.  Make a note where the seedlings were located and follow up the next season to make sure they’re not sprouting up again. It is best to cut the Ailanthusin in the early summer to “hit” it when its root reserves are at their lowest. Constant removal of the photosynthetic leaves will eventually starve the plant of food.

Leonurus cardiaca, motherwort, is an herbaceous perennial plant in the mint family, Lamiaceae. This plant  flowers May through August. The plant can spread rapidly, both by reseeding, and by sprouting vegetatively via rhizomes, sometimes forming dense colonies. This is an excellent factsheet on how to go about controlling this plant.

There are two other methods that might be helpful- the first is covering the area with dark plastic. This starves the weeds since they cannot produce food, another is covering the area with clear plastic which kills the weeds underneath due to high temperatures. The following is from one of our earlier posts:

The black plastic method of weed control works by starving the weeds:  they cannot produce food through photosynthesis and eventually will exhaust their food supply and starve. This method takes time and will only work as long as no light reaches the plant.

The clear plastic technique of weed control eradicates weeds by solarisation i.e. subjecting weeds to lethally high temperatures. This method works during a hot period of the year and when the soil will receive the most direct sunlight.

You can find more details on these two methods of weed control here:

Good Luck