Can grasses be planted first right along the bank to minimize trees falling into the channel?

Yes if conditions permit.

Buffer design should be very flexible not only to fit the biological and physical constraints of the site but also to meet the objectives of the landowner/farmer and the cost-share programs that might be used. As a result any combination of trees, shrubs or grasses is possible. However, Where banks are vertical and unstable it is best to plant woody plants as close to the bank as possible. If there is concern of trees falling into the channel then shrubs can be planted first.

A typical design that we often use consists of a row of shubs right next to the creek followed by rows of trees and then rows of shrubs. In either case a cover of grasses is also desired if the area was in row crop agriculture or the woody plants should be planted into existing pasture grasses using herbicides to control a narrow strip where the woody plants will be planted. If banks are sloped at 2:1 or better than grasses, preferably a mixture of native grasses and forbs, can be planted. If cool-season grasses are planted a waterway mix can be used.