Remember the Carly Simon/Jimmy Webb duet, "Spring Will Be a Little Late This Year"? Well, this year it's fall that's a little late. As recently as a few days ago, the foliage outside my windows still looked pretty green. Some people are calling the season unusual, but a better description might be patchy.

Many people are waiting impatiently for that annual display of vivid color in back yards, parks and woodlands. So what's going on? Both dry conditions and unusually warm conditions can delay the leaves' turning, and we've certainly had some of both in the past couple of months. The best conditions for good fall color include a warm, wet spring, a summer that's not too dry or too hot, and a fall that offers warm, sunny days and cool, not frosty, nights. (Frost will kill the leaves and can prevent them from changing to bright colors.) Those conditions have just begun to happen in this region.

Leaves change color because decreasing sunlight causes chlorophyll production to dwindle and stop. The yellow xanthophyll and orange carotene colors are always present in the leaves, but when the leaf is busy turning water and carbon dioxide into the sugars the tree needs to survive, the green of chlorophyll, which is essential to the process, dominates. With less and eventually no chlorophyll present, the other colors begin to show.

The reds, purples and more orange hues come from anthocyanin, which some trees produce to help extract all the nutrients from the dying leaves. Tannic acid in some trees will cause leaves to brown and die instantly without spectacular color.

As you are surrounded by fall foliage in the coming weeks, take notice of the transition and what color trees are turning -- and consider planting a palette of your favorites. Nature decides when the colors appear, but you can stack the deck in your favor by planting trees that, under the right conditions, will give you the most vibrant show.

Many factors will affect your results. Trees in the same genus might turn different colors. For example, oaks can be red, russet or brown. The amount of sunlight reaching individual leaves can also make a difference. Leaves directly exposed to the sun might turn red, but leaves on the shady side of the same tree -- or on other trees that are in the shade -- might be yellow. Temperature, sunlight, rain and frost also affect coloration. So plant for the color you want and hope for good conditions to bring out maximum brilliance.

Trees are the source of most fall color, and there's a wide variety for you to choose from, including sugar maple, sourwood, katsura tree, red maple, Japanese maple, black gum, sweet gum, sour gum, American elm, white oak, stewartia, chestnut, hickory, birch, European hornbeam, hawthorn, beech, gingko, common dogwood, Kousa dogwood, red oak and common bald cypress.

Don't overlook shrubs, which can also add to the fall color mix. Here are a few of my favorites:

* Winged euonymus (Euonymus alatus) is also called the burning bush because it has a fiery red color for a long period in fall. The leaves create a shiny red carpet around the plant, holding their color even as they fall. This shrub is falling from favor, however, because it's a non-native plant that, since being introduced here, is taking over our woodlands and robbing native plant habitats.

* Virginia sweetspire (Itea virginica) is a plant that will spread by stolons, or aboveground shoots, and create a colony of maroon color at this time every fall.

* Crape myrtles (Lagerstroemia hybrids) turn orange, red or bronze. Some can be spectacular in fall, though most are grown for their showy July-to-September flowers.

* Nandinas are broadleaf evergreens that turn red in fall, and, if the winter is mild, the leaves persist and will stay extremely colorful almost into spring.

* Common witch hazels (Hamamelis virginiana) turn yellow in fall and grow in woodland areas. They have a fragrant yellow flower in autumn as well.

* Doublefile viburnums (Viburnum plicatum var. tomentosum) display rich red to maroon foliage.

The healthiest trees and shrubs will produce the best foliage. Give those you plant now a head start by installing them properly. Dig as wide an area around the planting hole as is practical, and add 20 to 30 percent organic material to soil as you dig. Feeder roots spread horizontally over a long distance, and even the largest hardwoods absorb nutrients from the top two feet of soil.

If your preference is to see colors in their natural state and you want to take a leisurely day-long scenic drive, a few locations coloring now are: Skyline Drive, located in Shenandoah National Park in Virginia about an hour's drive west of Washington; the Blue Ridge Parkway, which begins on Skyline Drive and stretches more than 400 miles, connecting Shenandoah and Great Smoky Mountains national parks; Harpers Ferry National Historical Park, about an hour's drive from Washington, in the mountains on the border of West Virginia; Sugarloaf Mountain in Maryland, about 45 minutes north of Washington a short distance from Route 270; Cunningham Falls State Park, in the Catoctin Mountains about half an hour north of Frederick on Route 15; and Deep Creek Lake in western Maryland, about a two-hour drive away. All of these areas offer hiking, biking, and many opportunities for stops at overlooks or scenic viewing areas along the drive or once you arrive at your destination.

Closer to home, a few places to enjoy local color are: Rock Creek Park; the C&O Canal, which starts in Georgetown and extends to Great Falls Park; parts of the George Washington Memorial Parkway, along the Maryland and Virginia sides of the Potomac River; the National Arboretum, 3501 New York Ave. NE; and Brookside Gardens, 1800 Glenallan Ave., Wheaton, Md.

For a fall color report check Or, like me, you can just keep looking hopefully out the window.

Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site

The amount of sunlight that reaches leaves can affect what color they change to in the fall.