On the 24th of August, I posted some pictures of the ISU intramural fields following 3 days of continuous flooding. The warm-season grasses had recovered well from the flood, but the surrounding Kentucky bluegrass/perennial ryegrass area appeared to be dead.
The pictures below are from September 6, two weeks later. The area has been reseeded, but seedlings are not emerging at this time. The strip through the middle of the field are the warm-season grasses that recovered immediately after the flood. Notice the green area to the left. That is Kentucky bluegrass recovering from rhizomes.
The grass in the background is Kentucky bluegrass. No rye can be found in the area. The rye is a bunch grass and lacks a rhizome system. The rhizomes of the bluegrass are causing the recovery.
Here is a bluegrass plant growing at the end of a rhizome. This type of growth is what comprises most of the green tissue on the Kentucky bluegrass area.
A little digging in the area shows rhizome tissue just beginning to form new plants.
These new plants from these rhizomes will emerge in the next few days and begin to produce chlorophyll. I would expect recovery from rhizomes to be complete before fall and long before the new seedlings mature. Seeding is still a good idea on an area like this. The perennial ryegrass on the field will come from seed.
I'll keep you posted on the recovery through the fall.