Dying Grass - it just keeps getting worst
Dear Garden Expert, The grass in our front yard has steadily been dying over the last 1.5 years. I have attached before (2012) and after (2018) photos. The trees were smaller 6 years ago. There is more shade but there is sun light in the area where the grass has died. The trees are maples. I recently planted goldenrod and white wood aster under the trees. The Asiatic garden beetles have eaten many of the leaves. I spayed the plants directly with neem to attempt to control the bugs and have had some luck. I mention this because I often wonder if the problem is grubs. I also need to share this sod story - in case you think it is related to the problem. The timing is very suspicious. About 2 years ago, our neighbor replaced their entire front yard with sod. I transplanted a few pieces of the left over sod from their project into our yard. About 6 months later, the contractor removed all of the sod from my neighbor's front yard and replaced it with new sod. This, strangely enough, is when our grass started dying. The dead zone is around the area where the sod was planted. I asked our neighbors why they replaced the sod but never got a good answer. We gathered soil samples for testing in March 2018. Because we decided to mulch the area and plant native species plants in lieu of grass, we followed the garden plan. The soil test report is attached. We applied lime and starter fertilizer with phosphorous. The grass showed signs of improvement but that quickly faded. We also spread leafgro in the problem areas. With the beetles eating our plants and something killing our grass, we are scared to spend more money on the front lawn or native sedges but we would love to have a pretty yard again. Your time and suggestions are very much appreciated.
Montgomery County Maryland
Based on what we see in your photos, it looks like your best course of action would be to do a lawn renovation in the fall. In order to determine if grubs are present, you would have to tug at a section of lawn and see if it peels back easily (like rolling up a carpet). See if beetle larvae (grubs) are present. Typically grub treatment isn’t necessary unless there are 6-15 grubs in 1 square foot (depending on the type of grass you have). You can read more about this on our webpage about grubs. https://extension.umd.edu/hgic/grubs-lawns
I encourage you to read through our publication on Lawn Establishment, Renovation, and Overseeding. How much sun does this area receive? If you have full sun to moderate shade, a turf-type tall fescue is recommended. If it is shady, fine fescues are the most shade tolerant type of grasses.
The steps for lawn renovation are outlined on the following page. Fall is the best time to renovate. https://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/hgic/HGIC_Pubs/lawn_pubs/HG10...