While driving down the highway in recent weeks, have you wondered why the leaves seem to be changing color prematurely? Slender threads of vermillion weave through an otherwise green canvas; a russet drape over a sweep of shrubbery. We stand barely on the threshold of autumn. Nights are warm, gardens still bursting, and new school shoes not yet scuffed. Why the hurry?

Any entrepreneur will quickly tell you that the first step toward success is getting the customer in the door. And the way to do that is with an eye-catching advertisement. Mother Nature is nothing if not a shrewd businesswoman. She uses this same strategy.

Those ruby to garnet threads of Virginia creeper vine snaking up tree trunks are nature's billboards for advertising cheap easy eats. How else could a flying traveler discern them among the late summer greenery? Fruit eating birds dine at a country buffet while the vines have their seeds processed, packaged with fertilizer and dispersed. For added variety, grape vines display a deep maroon while poison ivy flaunts autumnal shades of yellow and pumpkin-orange. These early color changes are referred to as "foliar flags."

The key to nature's neon is contrast - both between one plant and its neighbors, and between the fruit and its surrounding leaves. The round ivory fruit of the gray dogwood against its wine-red foliage and cherry-colored pedicels (fruit stems) doesn't politely beckon to passing birds, as much as it shouts.

The position of the fruit on the branch also determines whether or not a plant needs to advertise. Remember that other cardinal rule of business - location, location, location! A fruit perched on the edge of a branch already has the advantage of visibility. The native spicebush carries its soft green leaves horizontally throughout the summer. Once its fruit ripens to red, the leaves turn a buttery yellow and droop, making the fruit much more visible. Clusters of fruit on the sumac or the non-native magnolia have all of the visibility of a vendor on a city sidewalk, so extra advertisement isn't necessary. The dogwood tree, by comparison, compensates for its slightly smaller portion by enhancing presentation.

We don't see these hot flashes of color in early summer foliage, with the exception of an occasional red leaf or two. Because changing leaf color means losing the ability to photosynthesize, a plant that did so early in the season would also lose valuable growing time. Besides, there's no need to advertise. Early fruiters, such as the nannyberry shrub or the shadblow tree, cater to the locals, who always know the best spots to dine.

Whether locals or tourists, we can scan the roadsides from a new marketing perspective and wish the migrating birds bon appétit and bon voyage.