Flower beds look better if bordered with some synthetic barrier or hedge plants. This bordering can be done using stones, bricks or low growing hedges/ground covers such as Alternanthera(commonly known as nanthra or china grass). This low growing herbaceous perennial is trouble free, fast growing, economical and easy to propagate. What sets this plant cut above, from others in this category, is very easy propagation. Just poke 2-3 inch cutting in the soil and it will root in few days provided its kept moist. Best time to propagate nanthra is spring or monsoon. In frost areas, it will get damaged in winters but will spring back in spring season.
Advantages Over all better appearance of the bed. Formal appearance if trimmed properly(box shape). Protection from inadvertant stepping over the border. Demarcation and prevention from soil erosion. Limiting of plants to grow in the designated/bordered area. Eye catching fall color(Red).
Disadvantages Increased Water requirement overall(though alternanthera is drought resistant itself) Roots intruding flower beds requiring restriction, may be through hoeing. Fortnightly trimming requirement in active growing season(spring/summer).
Yes I agree. Bordering your side plants with some thing like Alternanthera looks very organized and good on eyes. It is very common here in Rawalpindi/Islamabad. I also had it in most part of my about one canal garden at Kharian. Here in Pindi it is struggling due to cold weather, but it will recover soon, as it usually does once weather gets better. By the way good little nursery you have at your place, MashaAllah. I wish I had this much space in my current home at Pindi.All the best.