If you buy potted plants or shrubs, they may well be root-bound. With nowhere else to grow, roots form tight circles inside the pot. As the plant grows, the tightly wound roots prevent water and nutrients from reaching the leaves.
1. Before planting, gently coax these roots outward with your fingers.
2. If the roots are very stubborn, make three or four vertical cuts in the root-ball with a sharp knife. Once planted, water often to help the plant get established.