October in the garden: After hard frost is prime bulb-planting time;

Fall is the season to select and plant bulbs for spring blooms. Investing some time and energy at the end of the gardening season can provide a great show in the spring.

Most bulbs should be planted after a hard frost, from mid-to late October until the ground freezes.

When buying in a garden center, pick bulbs that are plump and firm with no mushy spots. Small nicks, loose tunics or blue/gray mold do not affect the development of bulbs. But bulbs with white mold or that are soft and lightweight with a strong moldy smell are probably not good.

If you cannot plant your bulbs right away, store them in a well-ventilated area that is cool but above freezing, out of reach of rodents. Keep them away from ripening fruit, which emits ethylene gas that can harm the bulbs. Artificial heat will dry bulbs out and high temperatures may destroy next spring's flower inside the bulb.

Plant bulbs so the bottom is two to three times as deep as the length of the bulb in well-drained soil. Plant bulbs with the pointed end up.

General garden care

Cut back perennials when they start to look bad. I prefer to leave up as much of the dried plants in the perennial border as possible for winter interest and then cut them back in early spring.

However, if you have had problems with meadow voles feeding on tree bark in past winters, cut back vegetation at the base of trees and shrubs to take away cover for them to hide in.

Plant ornamental cabbage and kale for annual color accents in fall. Incorporate them into existing beds or tuck them into containers. These annuals are most colorful in cool weather and can maintain their display quite late in fall. Ornamental cabbage is smooth-leafed; ornamental kale is curly-leafed.

August and September were dry, so provide supplemental water this fall to new plants installed over the last two to three years. Newly planted evergreens are particularly vulnerable if they go into winter without being regularly watered in fall. Evergreens continue to lose water through their leaves during winter and their needles and leaves can easily dry out. Be especially careful to keep watering evergreens that are planted in containers during dry and warm periods throughout winter.

It is too early to prepare your hybrid roses for winter. Wait until there have been two to three hard freezes with temperatures in the teens, which typically occurs in late November at the Chicago Botanic Garden. Once freezes have sent the roses into dormancy, tuck them in for the winter by mounding crowns with 12 to 15 inches of compost and cutting the canes back to the top of the compost mound. Landscape or shrub roses do not require this special treatment for the winter. Treat them as you do your other flowering shrubs such as lilacs and viburnums.

Certain bulbs, such as daffodils, hyacinths, tulips and crocuses, are excellent for forcing in pots in the greenhouse or home. They need to go through a period of cold dormancy, so they must be chilled for six to 10 weeks at 40 degrees or below. Plant them in pots in the fall and leave the pots in a cold place, such as an unheated garage or crawl space. You also can sink the pots up to the rims in the ground in a cold frame and cover them with mulch. Water the pots and do not allow them to dry out. In late February or early March, acclimate the potted bulbs gradually to inside conditions, keeping them at 50 to 60 degrees for a few days. Then grow them in a bright sunny location indoors until they bloom.

Buckthorn is an invasive tree and common throughout the Chicago area. Late in fall is a good time to recognize and remove it, since it tends to hold green leaves later than other deciduous trees. Cut the buckthorn trunk off at the ground level and quickly treat the stump with an herbicide containing glyphosate, such as Roundup, to kill the root system.

After a killing frost, remove dead plant debris from annual and vegetable beds. Sanitation is especially important if you have had disease problems in your garden. Remove all diseased foliage or fruits and put them in the landscape waste, not the compost pile, as most home compost piles do not get hot enough to kill disease organisms.

Terra-cotta containers need to be stored out of the elements for winter. These containers absorb water and the freeze-and-thaw cycles of winter can crack them if they are left outside. When plants in these containers are finished for the year, dump out the growing medium and store the pots in a garage or shed so they are out of the rain and snow. Placing these pots in plastic bags and leaving outside can still result in broken pots if water finds its way inside the plastic.

The average first frost at the Chicago Botanic Garden is Oct. 15, though it is often later in the city. Tender plants can be protected from light freezes by covering them with sheets, landscape fabric, plastic or boxes. But when night temperatures begin dropping below 40 degrees, it is time to bring in any tropical plants you are keeping outside.

Warm fall days are great for installing Christmas lights. Wrap branches of your trees with strings of lights to accent the tree's form. Many people wait until late November, when it is much colder, to string lights, but the Chicago Botanic Garden staff starts installing thousands of twinkling lights in early October.

Yews and arborvitae can be ruined by deer browsing over winter. If you have had deer browsing in your garden, it is time to cover vulnerable plants with netting. I use twist-ties to secure the netting.

Lawn

Continue cutting your grass throughout the fall as needed. Cold weather will eventually stop grass growth. Make your last cut of the year at a lower-than-normal height of 2 inches. Take care to stay off the lawn when there is heavy frost present.

If you are following an intensive lawn maintenance program, make your last application of lawn fertilizer in late October or early November if you are following an intensive lawn maintenance program.

Use no more than 1 pound of nitrogen per 1,000 square feet of grass. To calculate the amount of fertilizer to apply, divide the rate of nitrogen to apply per 1,000 square feet by the percent of nitrogen in the bag (first number of three listed on the bag, use decimal form). Multiply this answer by the square footage of lawn and divide by 1,000. Here is an example: You have purchased a 24-0-10 bag of fertilizer and have 5,000 square feet of lawn to fertilize at a rate of 1 pound of nitrogen per 1,000 square feet. So 1 pound of nitrogen divided by .24 equals 4.17; 4.17 times 5,000 square feet of lawn equals 20,850; 20,850 divided by 1,000 equals 20.85 or about 21 pounds of 24-0-10 fertilizer required to cover the entire lawn.

Applying too much fertilizer can pollute water sources and cause grass to grow too fast, leading to more work for you and bigger chance of disease problems.

Schedule a time now to have your sprinkler system drained for winter instead of waiting for the first severe cold to be predicted. Water left in the system can freeze and crack sprinkler heads and pipes. Compressed air often is used to blow water out of the system.

ŸTim Johnson is director of horticulture at the Chicago Botanic Garden (chicagobotanic.org).