Typically seasonally, but tailored schedules depend on local conditions and plant types.

Mowing your grass regularly, especially if you’re mowing close to the ground, can help kill Johnsongrass. Frequent mowing helps limit the spread of Johnsongrass and can even deplete carbohydrate reserves in rhizomes over time. The more time you leave in between mowing, the more likely Johnsongrass is to regrow and take over your lawn. 

Weed control applications usually cost around $100 each for a standard-size yard, and most professionals charge between $30 and $60 per hour for manual weed removal. Your total is affected most by the size of the weeded area. Some weed service companies offer weed control treatments, selective herbicide spraying, and manual removal and upkeep as part of a package, costing around $600 annually. You might pay less if you hire the same company for other lawn services, like flower bed upkeep, aeration, overseeding, and pesticide application.

If you have a lot of tree roots in your yard or have experienced issues in the past, you should use tree root killer every six months to prevent roots from infiltrating your pipes. If you have an active invasion and aren’t seeing results, check the instructions on the bottle to see how often you can use it in a short period of mine.