People always ask about maintaining the garden, and what to do with all the tall grass and seed head. Leave them or cut them back? The Answer is "yes". It is all about a balance. leaving the tall stems and seed heads add structure and interest in the garden through the winter. The seeds also provide food for birds and other animals. On the other hand, cleaning everything up (cutting thins back and building brush piles with the materials), leaves the prairie ready for the spring and the small, "under-story" early spring flowers will really shine. So it is all about maintaining a balance. Normally I cut about half or more of the prairie back in the fall and leave some grasses and forbs tall through the winter- just a way I find aesthetically pleasing.
Though last fall I didn't really cut anything back and this winter I've been a little stressed about getting all the leaves and grasses cut back. If left they form a mat and mildew or mold grows- until the summer that is, which is fine, but it really puts a damper on the spring ephemerals like the bitterroot (Lewisii redivia), sagebrush buttercup (Ranunculus glaberrimus), larkspur (Delphinium bicolor), yellow bells (Frittalaria pudica) and shooting stars (Dodecatheon conjugens). In nature, or outside of 8th Street, grazers, browsers and fire would do this seasonally.
But in our neighborhood, we don't have elk, deer, and although there are periodically fires in our neighborhood (not good), I think the neighbors would frown on intentionality setting a prairie fire, though my wife and I do think about it from time to time.
So while cutting back the prairie temporally removes all the structure we've been seeing this winter- the tall bluebunch wheat grass (Pseudoroegneria spicata) stems, the yarrow (Acheillia millifollium) and blanketflower (Gaillardia aristata) seed heads and the tangles of blue flax (Linum lewisii), it does reveal the green new growth and as soon as we get a day of sun (and the snow that fell last night melts) the tiny harbingers of spring, the sagebrush buttercups, will bloom.