Knowing your local nectar flows is an essential part of beekeeping. They tell you when to put on honey supers or if supplemental feeding is necessary. The nectar flows occur roughly by the calendar dates, but that formula approach is not sufficient. The plants respond to the weather. The weather is quite variable, so the beginning blooming dates of the plants become a variable too.
I watch the nectar and pollen plants for their coming blooms. Ultimately though, I watch the bees for what they are bringing in. Below is an account of nectar flows in my area of Eastern Virginia, mid Atlantic region, as an example. My methods can be applied to other locations further west.
Starting in early spring, bee flight begins on warm afternoons in late February. The returning foragers collect water desperately needed for brood rearing. Initially, no bees return with greenish pollen, the first pollen of the spring. That is because out in the woods, surrounding my rural apiaries, none of the maple trees have yet bloomed. Their buds have been swelling with each warm day. Soon the bees will find the early blooming maples somewhere out in the woods (see Figure 1). And the greenish pollen pellets come pouring in the hives. Occasionally, the maple trees I am watching for the blooms are still in bud stage. Having a maple tree to watch is good to know when the bloom will come, but that particular tree could be a late bloomer, an early bloomer, or one near the middle. I figure on the average, a tree in the city will probably bloom before a tree out in the woods because cities are typically warmer.
In the spring, numerous nectar and pollen plants each make minor contributions to the overall forage of a colony. For example, Mustard Greens, planted the previous summer for their leaves, remain in the field for the winter. In the spring, up grows a stalk and numerous yellow blooms appear (see Figure 2). Yellow Mustard fields hum with bees. Then the grower plows them, sending the plants underground, turning the fields from yellow treasures to dirt deserts, worthless for the bees, who move on. Red Bud is a small tree that blooms in the still leafless woods, a bright beacon of purple flowers, easily to spot (see Figure 3). It attracts all kinds of bees from the woods including honey bees. Sometimes I see my bees working wild Blueberries near my apiary, but mostly native bees pollinate that plant.
While the bees are building up on these minor nectar plants, I inspect the colonies to make sure they have enough food stores. At this time, colonies have large amounts of brood, which can deplete the food stores, especially if it rains for a week or so, preventing flight for much needed nectar and pollen. Conditions in a colony change quickly at this time of the spring. This build up time goes through March into roughly mid April.
Around late April, the plant bloom I am watching now is for …