If you have a sand-laid brick path, you will inevitably find the spaces between the bricks being colonized by weeds. If the microclimate is at all moist, moss will be a component of these weeds. Many gardeners find moss attractive. If you do, try selectively removing the grasses and other undesirable weeds and allow moss to remain. In this way, you will encourage this lovely green perennial to colonize and prevent the return of unsightly weeds.
Some people colonize the spaces with a spreading plant, such as thyme.
Scarlet pimpernel, an annual weed that appears in spring gardens, has a very prostrate habit, a short growing season and is a poor competitor with other plants. Furthermore it produces tiny red flowers. Because of these characteristics, many gardeners enjoy the flowers and let the plant die out on its own and mulch the soil. When weeds do exceed your tolerance, remove them, but tolerate those that aren't worth your time and effort to remove. Sheila Daar is Executive Director of the Bio-Integral Resource Center and an IPM specialist.