Peonies can now be planted, divided or transplanted

Peonies are dependable, long-living, hardy perennials. Their neat foliage stays green from spring until frost, and they show large, showy blooms.

They do best in full sun, although they can tolerate partial shade. Flowering is reduced if placed in the shade. September is a good time to plant peonies, as well as divide and transplant existing ones. Lift roots carefully and use a sharp tool to cut the large, fleshy roots into smaller pieces. Be careful not to make these pieces too small - each section should have at least three eyes. The eyes are reddish growing buds that emerge from the top of the roots. You will find them in spring and fall. Set these divisions an inch or two below ground.

• Plants that prefer acidic soil conditions like rhododendrons and azaleas can benefit from an application of granular sulfur to the soil in fall and spring.

If your blue hydrangeas have turned pink this year, then a sulfur application may return the flower color to blue. Avoid contact with the sulfur by wearing latex gloves and keeping dust out of your eyes. Apply to the soil and gently scratch in.

Sulfur works slowly in the soil and repeated applications will likely be necessary from year to year.

• It is time to start thinking about the indoor herb garden. Before frost, carefully lift and pot small herb plants or large perennials such as rosemary or lemon verbena to bring inside.

After lifting them from the ground, you may want to keep them outside for a few days in a partially shaded spot with even moisture. This will help them adjust to a move indoors.

The shock from moving plants from outside to inside can cause some yellowing of leaves. Once inside, keep the herbs in a sunny window.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.