Do it now
Perennials: Continue planting bulbs as long as weather permits. Pick the last roses of the season. Hill up soil at the base of the plant so that it covers the rose graft area to prevent winter kill.
Flowers: Replace flowering plants in window boxes and containers with evergreen branches and berries. The containers should be frost proof.
Vegetables and fruits: Continue to harvest root vegetables and Brussels sprouts, which are especially good with Thanksgiving dinner.
Trees and shrubs: Continue protection of shrubs from deer. Spray broad-leaved evergreens with antidessicant to prevent the loss of moisture. Apply when temperature is above 40 degrees. Protect shrubs with burlap if they are likely to be damaged by heavy snow. Move containerized shrubs into a protected area if possible.
Lawns: According to many lawn experts, the late November fertilizing is the most important of the year. This application will feed the root system in preparation for strong growth in the spring. Spread according to directions on the fertilizer bag. First, the lawn should be cut short to prevent fungus formation.
Houseplants: Give houseplants as much light as possible. Remember to let up on the fertilizer until spring.
General: Other late-fall chores to complete before the holiday distractions: drain and hang hoses and turn off outdoor faucets (but keep one available for continuous watering of new shrubs and trees during the winter); clean leaves off roofs and gutters; stack the firewood in a convenient place; buy stakes to mark driveway for the snowplow; fill bird feeders.