Fall flowers provide refreshing color

Try to buy mums and asters when their flower buds are just beginning to open. The color will last longer in your garden.

Generally, mums and asters last for four to six weeks depending on weather conditions. Season-extender mums will be available later in the season and can keep color going through October and sometimes later depending on weather.

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

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

• Continue to harvest vegetables as they ripen. Warm-season crops like peppers and tomatoes should be picked as soon as possible. Full-size pumpkins need to remain on the vine as long as possible to achieve their maximum size.

Continue to snip herbs to use fresh, to dry or to freeze. Try making some extra pesto and freezing it in an ice cube tray. Pop out the cubes when frozen and store in a plastic bag for use this winter.

Collards, kale and Brussels sprouts taste better if they are allowed to be hit with frost before harvesting.

Maintain good sanitation throughout the vegetable garden. Remove diseased plants immediately as well as those that have finished their growth cycle for the year. It is best to compost only healthy plant material.

• Ornamental onions (Allium) are some of the best bulbs to plant for resistance to animal browsing. They come in many varieties. Try the popular June-blooming Globemaster with a 10-inch pinkish-purple flower on a 2- to 3-foot stem; it lasts up to a month.

The drumstick onion (Allium sphaerocephalon) has reliable burgundy blossoms that are about 1 inch wide. Lily leek (Allium moly) is a small species, 10 to 14 inches tall, with yellow flowers.

These are just a few of the 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, while tulips and crocuses are readily eaten.

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