Most of us that hunt pheasants know that patches of sweet clover can be a pheasant spot to check, but that said ...

I was hunting an area of MN that used to be really good for me years ago. Not a core area, but can be good. Had to shorten the drive to make the day work.

To my dismay ...

Spot one which always shown me birds ... was covered in sweet clover. I would say 40% of the 40 acre side was covered with the sweet clover ... huge continuous runs of the stuff ... much of it 5 - 6 feet high. This was a WIA CRP plot. We found birds, but I could not see them flush because of the height of the sweet clover. Dog tough to find on point even with the Garmin Astro. I thing the bird I shot near my truck was pushed out of the clover by me earlier that morning.

Spot two ... farmer was disking the CRP grass in a WIA area. Not only did I lose the spot for the day ... it appears to be gone in the future

Spot three ... MN WMA ... the one side that I like to hunt looked great ... freshly combined corn edge ... but sweet clover was even thicker and more expansive than the first spot. Walking expansive areas of sweet clover 5 - 6 feet high is not something I plan to do again.

The weather is this area must have been absolutely perfect for sweet clover to have a growth advantage over the natural grasses that usually encompass those areas.

Sweet Clover was brought to North America as a forage crop and quickly escaped cultivation. It invades roadsides, fields, and generally anywhere soil is disturbed and can invade high grade prairie. It likes fire and can erupt in an explosion of growth following a burn. White Sweet Clover (Melilotus alba) was once classified as a separate species (Melilotus albus), then lumped in with Yellow Sweet Clover, and is back to a separate species again. Yellow Sweet Cover starts blooming a couple weeks earlier than White and is a slightly smaller plant, but except for the flower color and some other more subtle differences is otherwise nearly identical.
Sweet clover can grow nearly anywhere, with as little as 16 inches of rainfall per year. It has deep tap roots that mine soil nutrients and water from deep within the soil. It is better than many of the other clovers for nutrient recycling and appears to have a greater capacity to extract potassium, phosphorus and other soil nutrients from insoluble minerals. Sow in spring to summer at 1/2 lb./1,000 sq.ft. (15 lb./acre) as an annual, or let grow the next year over 6 ft. tall.
Moving back to my favorite areas soon ... longer drive ... but worth it.