While the plant is at its peak, you can make the most of your investment by reinvesting earnings , that is, multiplying the plant by division or taking cuttings . Sometimes, it's possible to start new plants from its seed. Each perennial variety, though, has its own preferred method for multiplying. For example, division works best with plants like day lilies, iris, and hosta. Most woody plants can only be increased by cuttings.
Division is the most foolproof method.
It allows you to start new plants from chunks of an established plant. The best time to do this is spring. If your climate has a long, warm fall season or mild winter, you might be able to divide plants in early fall and still get them well established before winter. An overcast, cool day is ideal for dividing plants but if the day turns out to be warm and sunny, be sure to shade the new plants or they'll die from wilting. Start by cutting back the tops of the plants you want to divide by one half to two thirds.