Rock Lining and Bolders
If you do not wish to do any extra work and yet require an effective flower bed border, rock linings are your sure answers. Lining the flower beds with rocks and boulders, in natural shapes and sizes, can actually do the trick for you. It does not require any laying and just needs someone to arrange the rocks in the required stylized shapes.
Irregular shaped Texas surface sandstone boulders commonly used to enhance landscapes.