A good edging between the lawn and your beds is the most  practical way to keep grass out of flower beds. An edging of brick, wood timbers or plastic edging that can be sunk into the ground at least six inches keeps the underground grass roots in check. Some gardeners just cut back the lawn every few weeks by using a sharp shovel to keep the edge defined. Hand pull any grassy weeds that blow in by seed. Keep growing, Marianne Binetti