Astilbe is a perennial plant native to North America and Asia. This flowering plant, like most perennials, can be divided. Astilbe does not need to be divided as often as other perennials, but will benefit from division every two to four years. An established astilbe plant should give you at least four new plants when dividing. These transplants can be established in other parts of your garden. When transplanting astilbe, it is important to give the transplants the best start by reducing shock, providing healthy soil and watering thoroughly.
Rake compost or manure into the soil around plants before dividing to increase the nutrients in the soil.
Water the astilbe plant until saturated--the soil around the plant will appear completely saturated. Watering releases the roots and lessens the shock when plants are removed from the ground.
Dig holes big enough for the roots of each new transplant. Make holes 6 to 8 inches deep and as wide as you plan to cut the new transplants.
Remove the soil around the outside of the main plant with a shovel. Working 2 inches away from the plant, moving in a circle to a depth of 6 inches.
Remove the plant by its base from the soil when it starts lifting from the soil. Keep the root ball attached to the plant.
Cut through the roots of the plant with a shovel, cutting from the top of the plant to the ends of the roots.
Cut through the roots in a few different places to make at least four transplants. Each transplant should appear to have a strong root system.
Insert a transplant into each hole. Pack soil lightly around each transplant.
Insert the original plant back in its original hole and pack the soil lightly around it.
Water the soil around each plant until well saturated.