There are many things that the seasoned beekeeper must learn. One of the most important things to know is when local trees and flowers bloom. Knowing when a nectar flow starts can help a beekeeper add additional honey supers if necessary. With this in mind, I have been paying extra attention to the wild flowers and trees growing in our area.
As the month of July winds down, we tend to have longer dry periods, but we are still treated with a number of wild and ornamental flowers. Here's the running list of species in my area, starting with the flowers I see the most frequently:

White Clover (Trifolium repens) While under-appreciated by most people, clover is a prolific flower which can produce nectar for most of the summer months. While its mostly found mixed with other grasses in your yard, some farmers will plant clover specifically as a feed crop. It is one of the favorite foods of cows, and one of the most valuable flowers for beekeepers. Honey marketed as wild flower honey generally contains a large percentage of clover. Clover also produces a very light honey, which makes it very desirable for food production. While there is no shortage of clover in our area, I only wish people would mow their yards less frequently, so my bees would have a longer time to harvest. Bees tend to forage for clover in the afternoon, once the dew has dried up.
Queen Anne's Lace (Daucus carota) If you drive anywhere in Kentucky you'll see an abundance of this wildflower growing in untended fields. According to what I've read, bees will not work Queen Anne's Lace due to its noxious odor. Some beekeepers say that it ruins honey by making it smell like body odor. Yuck! If that wasn't bad enough, when I was growing up, we called it the "chigger flower", because we thought that chiggers were attracted to the flowers. I'm not sure where that idea originated, but we can provide better forage for the bees.
Black-Eyed Susan (Rudbeckia Hirta) One of many flowers in the Aster family, this flower is also found frequently in roadside ditches and untended fields. There is a large cluster of this right in front of the hives, and I've never seen a bee on them. Still, articles I've read seem to indicate that they will provide some nectar and pollen.
Chicory (Cichorium intybus) Another common sight in roadside ditches, this bright blue flower has a faint smell and is a minor source of nectar. It is drought-resistant, which is an added benefit for flowers blooming in July and August. The root is used as a coffee additive (or substitute) and is also used in some stouts, including the very interesting Dogfish Head Chicory Stout. This started blooming near our house in the middle of August, and the bees certainly enjoy working these flowers.
Boneset (Ageratina altissima) Found mostly in moist alkaline soils, seems to prefer partial shade. This has just started blooming, so I expect to see more flowers appearing throughout August. My honeybees seem to prefer these flowers when they are still green, just as they begin to open up. Once they turn white the bees leave them alone. I found an abundance of this in the fields behind our house, and the pollinators keep the bushes buzzing with activity.
Goldenrod (Astereae Solidago) I couldn't forget to mention the state flower of Kentucky. Early varieties start blooming in mid to late August, but my bees haven't taken a liking them. The rest of the goldenrod starts blooming in early to mid September, where they are prolific in the surrounding fields.