Pink or blue? Apply sulfur to turn those pink hydrangeas blue again
Have your blue hydrangeas turned pink this summer? Plants like hydrangeas, rhododendrons and azaleas that prefer acidic soil conditions can benefit from an application of granular sulfur to the soil in fall and spring. If your blue hydrangeas have turned pink this year, a sulfur application may return the new flowers’ color to blue. Avoid contact with the sulfur by wearing latex gloves and eye protection to keep dust out of your eyes. Apply to the soil and gently scratch it in. Sulfur works slowly in the soil and repeated applications are usually required every year. Your local garden center probably carries elemental sulfur.
Peonies are dependable, long-living, hardy perennials. Their neat foliage stays green from spring until frost, and follows large, showy blooms. They do best in full sun, although they can tolerate partial shade. Flowering is reduced if they are planted in the shade.
Propagate your peonies
September is a good time to plant peonies as well as to 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 2 below ground level.
Bring those herbs indoors
It is also time to start thinking about an 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 moving indoors.
Don’t be surprised to see some yellowing of the leaves from the shock of moving plants from outside to indoors. Once you bring plants inside, keep the herbs in a sunny window.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.