Bermudagrass is a warm-season perennial that spreads by stolons (above ground runners). Because Bermuda grass is actually a southern states grass, it does not handle the cold Michigan weather good at all. It will appear dead or dormant in the spring often until Memorial Day and to then return to dormancy soon after Labor Day. It will be particularly aggressive in areas where soil temperatures are elevated (e.g. near roadsides, or in full sun areas). There a no effective chemicals that will remove Bermuda grass from a lawn without killing the good grass at the same time.