Plant mums and asters now

Try to buy chrysanthemums and asters for fall color when their flower buds are just beginning to open. That way, the blooms will last longer in your garden.

If you are planting mums into a shady site, it is best to wait until the flowers are open before planting. If the mums are tight in bud when they are planted in a shady area, the flowers may not open.

Typically, pansies will not develop much in autumn season, so it is best to buy large plants that are in full flower. Plant them close together for a better show.

Mums and asters purchased in early fall will last four to six weeks, depending on weather conditions. Other varieties of mums that will be available later in the season can keep color going through October and sometimes later, depending on weather.

Plants that prefer acidic soil conditions, such as rhododendrons and azaleas, can benefit from an application of granular sulfur to the soil in fall. If your blue hydrangeas have turned pink, sulfur applications may return the flower color to blue.

Avoid contact with the sulfur by wearing latex gloves, and keep the dust out of your eyes. Apply the granules to the soil over the plant's roots and gently scratch in. Sulfur works slowly in the soil, and repeated applications may be necessary from year to year.

Allium or ornamental onions are more resistant to animal browsing than many bulbs; tulips and crocuses are readily eaten.

Alliums come in many varieties. Try the popular June-blooming 'Globemaster', which has long-lasting 10-inch pinkish-purple flowers on 2- to 3-foot stems. The drumstick onion, Allium sphaerocephalon, has burgundy blossoms about 1 inch wide. Allium moly, lily leek, is a small species that is 10 to 14 inches tall with yellow flowers.

These are just a few of the many alliums that succeed with little effort in Midwest gardens if planted this fall.

Daffodils are also easy to grow and are resistant to animal browsing.

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