Emerald Lawn Care receives calls every year asking “Why does my lawn look good except for all the weeds around the edges?”
There are actually several reasons this is an issue on many lawns.
1) The concrete/asphalt of the driveway, sidewalks, curbs, and other hardscapes, gets hot during the summer. This causes the soil along these surfaces to get hot and dry out. The cool season turf we have in this area (Kentucky bluegrass and ryegrass) prefers cooler soil so it thins out or recedes. The weeds, especially crabgrass and spurge, love the hot, dry conditions and they fill in the thinner areas.
2) It is common for this area to be edged with a string trimmer and scalping the turf is common. This shocks or even kills the grass, causing the area to thin out and the weeds to fill in.
3) Frequently, salt is used to treat the surfaces to remove snow and ice. When winter is over, and the lawn begins to come back, it doesn’t do well in the areas along the salt treated surfaces. Many weeds are more tolerant of the high salt concentration and fill in those areas where the turf is not doing well. Edging with a steel-bladed edger also exposes bare dirt at the edges of the hard surface which is an invitation to weed development.
4) Sometimes a lawn care technician, in an effort to keep lawn care products off of hard surfaces, does not get enough product applied at the edges. Insufficient crabgrass pre-emergent is very common since this is commonly applied as a granular product and is more difficult to control along the edges. The added heat common in these areas can also cause pre-mature breakdown of herbicides.
5) Areas along driveways and roads are frequently driven on by mistake. The weight of a vehicle causes substantial turf damage and compaction, and of course, there is an abundance of weeds that thrive in damaged areas and actually prefer compacted soil.
You can see that there are multiple potential reasons you might be struggling with this issue. As with many lawn issues, raising the mow height can help. Leaving the edges untrimmed also might be a solution. If salt is the culprit, a calcium or gypsum application might be the answer. In almost all cases, more water will help. Or maybe it is as simple as taking the keys away from your teenager who keeps driving on the lawn!