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<\/figure>\n\n\n\nMowing\u2019s<\/a> a different story, but read it right. Every time the top gets cut, the plant has to burn stored sugar to grow the leaf back, and if that happened often enough it would starve the root eventually. It doesn\u2019t happen often enough. <\/p>\n\n\n\n A lawn cut on the usual weekly or fortnightly round gives the thistle all the time it needs to regrow and push that carbohydrate back down into the root<\/a> before the next pass. So mowing is something you do alongside a herbicide \u2014 the cut plant takes the chemical harder \u2014 never the thing that gets rid of it.<\/p>\n\n\n\n This is the part that does the work, and most of getting it right is timing rather than product.<\/p>\n\n\n\n A selective broadleaf herbicide takes out the thistle and leaves the grass standing \u2014 the 2,4-D-based lawn products are the usual choice. <\/p>\n\n\n\n Systemic chemistry is the point. It moves down into that root system instead of scorching the leaf and leaving the rest alive. Pick a still day, 65 to 85\u00b0F, with wind under about 5 mph so nothing drifts into the borders. That part\u2019s easy enough.<\/p>\n\n\n\n Here\u2019s the part people get wrong. <\/p>\n\n\n\n Spray in the heat of summer, and the plant is running sugars upward into leaf and flower. So that\u2019s where the chemical ends up, in growth, it\u2019s about to drop anyway. Wait for fall. <\/p>\n\n\n\n As the season turns, the thistle<\/a> reverses direction and starts hauling energy down to overwinter the root, and herbicide put on then goes along for the ride, straight to the one place it has to reach. Fall is the most effective window there is for exactly that reason.<\/p>\n\n\n\n Spring gives you a second shot if a patch is already up and obvious. Hit it mid to late spring once most of the shoots have broken ground, come back over it in late summer or fall, and you\u2019ve caught the same plants twice in a year. You\u2019ll want to. One pass rarely finishes a thistle.<\/p>\n\n\n\n And don\u2019t expect it to. On a stand that\u2019s properly rooted, clearing it can run to several applications across a few years, because there\u2019s enough reserve in six feet of root to throw up survivors after the first hit. <\/p>\n\n\n\n Fall spray, look again in spring, treat whatever came back, and keep at it until the shoots quit. Treat it once and tick it off, and next summer it\u2019s back at full strength.<\/p>\n\n\n\n Thistle gets in through thin turf, and thick turf<\/a> is the only thing that keeps it out for good once the patch is cleared.<\/p>\n\n\n\n The seedlings can\u2019t handle shade. <\/p>\n\n\n\n A dense canopy keeps the soil surface dark enough that they never establish, which is why fast establishment and thick cover<\/a> are the whole foundation. So a tight sward shades them out, and a thin patchy one hands them an opening. <\/p>\n\n\n\n Assume the seed is already there waiting. It blows in from over half a mile off and sits viable in the soil for the better part of twenty years, so the soil around any lawn is holding a reserve of it. Whether it ever becomes a problem comes down to one thing: whether it lands on bare ground.<\/p>\n\n\n\n Even watering is most of what keeps that ground covered. <\/p>\n\n\n\n Grass grows<\/a> thick where moisture is steady<\/a>, and the spot that thins is always the one the sprinkler underdoes, the dry corner, the zone that never gets quite enough, the strip the coverage misses.<\/p>\n\n\n\nKill It at the Root<\/h2>\n\n\n\n
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<\/figure>\n\n\n\nClose the Gaps It Needs<\/h2>\n\n\n\n
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