Care of large blue grama field
We replaced blue grass/fescue with blu grama from seed on our large church property in Greenwood Village in 2010 to create a meadow look and save water. Unfortunately, within a year, Greenwood Village had changed its mind, requiring us to keep the grass length at 8 inches or lower. The past two years, we've cut in a three-week rotation, one-third every three weeks. This year, some brilliant mind hired a lawn service and now we're cutting the blue grama to 4 inches every other week.
Meanwhile, we're still trying to take advantage of the grass's drought-resistant qualities and save water. Not surprisingly, the light green color is not as pleasing to many as the deep green of a well-watered blue grass/fescue lawn. It's not as thick as it could be, so it's susceptible to thistle, in particular.
I'm worried about the blue grama's future. Would you please give me suggestions on how to prepare this field as we head into cooler fall and winter? Proper x-x-x mix of fertilizer? Are we mowing too much? Do you have a recommendation for a weed-control product?
Thanks for your help.
Arapahoe County Colorado
My apologies for this delayed response.
Blue Grama is the State Grass of Colorado. It is a warm-season grass, greening up in May and turning dormant-brown with arrival of cold nights in October.
It is a bunchgrass - does not spread, but individual clumps can expand in diameter. As a bunchgrass it is prone to weed invasion between clumps.
Suggest you fertilize it in the heat of summer - once in June and once in July.....Apply a 30-0-5 or 28-3-3 or similar fertilizer at 2.0 lbs/1000 sq ft (85 lbs/acre); follow with watering.
Blue grama will be best when mowed as high as possible.
There's been very little research done on weed control in blue grama lawns, as it is so rarely used as a lawn. Few if any post-emergent herbicides are labeled for use on blue grama lawns. I'd suggest you use glyphosate (Roundup and other trade names) as a spot-spray onto thistle leaves, whenever you see them. Avoid glyphosate contact with leaves of blue grama.
You can also apply glyphosate to thistle leaves in spring before blue grama greens up; there is less danger of injury to blue grama when it is dormant-brown.
Consider overseeding the blue grama with more seed anytime late May-early August. This may help to add density and competition for the thistle.
Blue grama seed is expensive; named varieties include Hachita, Lovington and Alma.