Control of size, rejuvenation and propagation are three main reasons to divide perennials.

Due to our cold winters, it's best to divide these perennials in early spring as they begin to grow. As the perennials expand [1], the outer parts thrive in fresh soil while the inner parts suffer and die from lack of moisture, nutrients, light, and air.

To prevent this from happening, carefully dig up the plant and pull it apart [2]. Then carefully cut off the dead stems, leaving the heathiest portions of the plat intact.

Next, dig a hole larger than you need and add a compost mixture or a well aged manure mixture with the soil [3]. Set the plant in the prepared hole and spread out the roots. Carefully place soil around the roots. Be sure the crown is replaced at the same level.

Use a water soluable fertilizer, mixed at half strength, and water thoroughly. After the soil has settled, fill in soil around the plant and water again.