My lawn is very healthy and happy, but all around the paved margins of the lawn crab grass is growing. The crab grass does not grow where the lawn abuts unpaved ground. For example, where there are mulched areas or wooded areas or forested areas, there is no crab grass. It is only where the grass meets asphalt or brick pavers in the walkway. The crab grass is much more prevalent along the asphalt than the brick walkway. Along the walkway there is only a crab grass plant here or there, but along the asphalt it is solid crabgrass.

The soil is marine clay (leda) and climate is New England coastal.

Why is crab grass growing in these margins and how can I get rid of it and get lawn right up to the asphalt?

Is the asphalt poisoning the lawn? Do I need to put some kind of buffer there like brick pavers along the asphalt?

1 Answer 1


Two things to consider here: the type of soil close to your hard surfaces and temperature and humidity in the two microclimates. Basically nature is just doing its job here, selecting the most appropriate plant material for the location. Crabgrass likes hot and dry conditions where there is no competition from other grasses and plants and drainage is good. The finer grasses like things cool and humid where the moisture hangs around and the sun's effect is not so intense.

If you were to set up a data logger by the side of the hard surfaces and register temperature and humidity and do the same thing simultaneously by the woodland likely you would see much higher temperatures and lower humidity near the driveway. Combine this with the sandy substrate laid down by the driveway installer that will bleed over into the lawn area and you have ideal conditions to drive out finer grasses and leave the default to crabgrass. (You can check soil quality by taking samples and doing a mason jar test.) By the woodland the crabgrass will not survive because it will be crowded out by the finer grasses and intermittent shade.

So the solution would be to improve the areas close to the hard surfaces: improve the water-retaining properties of the soil there with additives, make sure that area gets a good share of the irrigation, and if you can consider it paint the edges of the driveway white to reflect the sun's rays back up and not absorb the heat. This would be similar in effect to your brick edger idea. You could attempt this on a select area to see if it works. The theory is good.

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