Honey Bee Pollen Timing Chart

Beginning Beekeeping

Beekeeping is a fun and challenging enterprise. There is an increasing interest in beekeeping in South Carolina, in part due to the recent reports concerning honey bee losses in the country and also due to an increased awareness of the importance of pollinators and the health benefits of locally-sourced honey.

One of the keys to successful beekeeping is understanding what honey bees eat and what food sources they use to maintain productive, growing colonies. While it is generally understood that honey bees collect nectar from flowers and use it to make honey, nectar and honey comprise only part of the honey bee diet. It is the pollen that honey bees collect from flowers that provides the proteins and fats necessary to raise honey bee larvae and grow the colony.

Beekeepers should watch the hive entrance for foragers bringing pollen into the hive.
Barbara Smith, ©2021, HGIC Clemson Extension

The Missing Link – Pollen Sources

Honey bees raising brood must have pollen, and in South Carolina’s mild climate, most honey bee colonies continuously raise brood year-round, although it slows significantly in winter. For this reason, beekeepers must be able to identify the pollen sources around them and learn the seasonal changes that occur in pollen availability. Honey bees will search for suitable plants as far as two miles from the hive, harvest pollen from those plants and bring it back to the hive. This means that the nutrition of the honey bee colony is directly dependent on the community of plants surrounding the colony. Even in natural settings, there may or may not be suitable pollen sources available to the colony, and human land uses such as forestry, agriculture, and development further change what pollen sources are available for the bees.

Pollen and nectar availability also changes seasonally. Across most of South Carolina, the spring months bring a surplus of food for bees as many wild plants bloom during what most beekeepers affectionately call the spring nectar flow. There are also a number of very important pollen plants, such as the early blooming red maples (Acer rubrum) and dandelions (Taraxacum spp.), that supply pollen necessary for honey bee colonies to grow in the build-up before the spring nectar flow. After the spring nectar flow subsides, many parts of South Carolina enter a pollen and nectar dearth (a period when few plants are blooming) that intensifies as the summer progresses. While some natural areas may fail to supply large volumes of pollen during the summer dearth, beekeepers in agricultural parts of the state often experience increases in pollen collected from summer blooming crops such as cotton, beans, and melons. This shows that the intentional addition of plants utilized by honey bees can supply nutrition for the hive, especially in times and places where natural forages are not available. The fall brings a second, yet usually less intense, pollen and nectar flow as goldenrods and asters bloom, and these fall-blooming plants supply critical nutrition for honey bee colonies as they prepare for the coming winter.

The Pollen Timing Chart

The Honey Bee Pollen Timing Chart helps beekeepers and landowners determine what combinations of plants they might plant on their property to maintain a pollen source for their honey bees over the entire growing season. Some honey bee forage plants may provide pollen sparingly but for long periods of time; others may provide a large amount of pollen over a short time frame. Planting mixtures of bee forage plants provides forage from many different plants over the year. Honey bees are generalists and need a diversified diet containing a range of minerals, amino acids, and fats, and each pollen source provides a different nutrient profile. Honey bee colonies intentionally collect pollen from multiple sources to diversify their diet. Honey bee colonies that are raised on a single pollen source have reduced fitness and productivity, and monocultural plant communities, such as those present in some agricultural and forestry land uses, are unable to supply pollen to bees through the entire growing season.

The chart provides a list of various plants commonly used by honey bees. All of the plants on the list may be grown in South Carolina’s climate. The estimated bloom periods for each plant are listed in a colored bar. These ranges of pollen production times are estimates and may vary slightly from year to year. Variations in temperature, such as early or late frosts, cool springs or hot summers, and the amount of rainfall will influence when plants bloom and for how long. The estimated bloom periods in the chart are averages, so plants on the list may bloom beyond the average bloom period due to the effects of local climate and site conditions. The beekeeper’s objective should be to plant a diversity of plants in sufficient quantity to provide a continuous source of pollen for the honey bees over the entire season.

Planting honey bee forages is an intentional agricultural practice that requires proper planning, site preparation, soil amendments, seed mixes, planting equipment, and maintenance. Beekeepers and landowners are encouraged to contact the Clemson Apiculture and Pollinator Program for additional guidance and to work with their local Extension office and agents for site-specific recommendations. Local Extension Agents can help with proper planting dates and information concerning soil testing, liming, crop rotation, and weed control to ensure the best crop production. For a listing of local Extension Offices, see Clemson Extension County Offices.

The types of plants may be changed each year as a beekeeper searches for the best mixture of forage plants for their own hives. The bees will also continue to range over the surrounding area, foraging other plants as their pollen becomes available.

There are other important pollinator plants available that are not included in this chart, many of which are pollinated by other types of bees and flying insects. The plants not listed in this chart are generally not heavily utilized by honey bees. Selecting plants that honey bees will frequent is an important step in any bee forage planting. The types of plants may be changed each year as a beekeeper searches for the best mixture of forage plants for their hives.

Monitoring for Success

There are several ways to determine if the time and effort planting pollen sources are helping honey bees and other pollinators. A simple method is to visit the pollinator plots during the day and look for foraging bees and pollinating insects. Both native bees and managed honey bees collect pollen and attach it to hairs on the body. Honey bees, bumble bees (Apidae), and sweat bees (Halictidae) attach pollen to their legs in pollen baskets (corbicula). Other bees, like mason and leaf cutter bees (Megachilidae), collect pollen on scopa under their abdomens. Bees visiting the pollen plants should be visibly carrying pollen on their bodies.

Honey bee colonies, in particular, can be assessed for pollen gathering in several ways. Beekeepers should watch the hive entrance for foragers bringing pollen into the hive. A few minutes spent watching the hive entrance and landing board will help the beekeeper determine if new pollen is being gathered and the colors of the incoming pollen. Beekeepers also can use a “pollen trap” device, which forces incoming bees to climb through small openings that removes the pollen from their legs as they enter the hive. Pollen traps come in various designs and are used to collect pollen for human use or for feeding back to bees during dearths. A pollen trap gives a beekeeper a method for measuring the actual volume of pollen entering the hive. Finally, beekeepers conducting normal hive inspections should look for “bee bread,” which is pollen that is stored in the honey comb for later use. Bee bread is typically stored next to developing brood (eggs, larvae, and capped pupae). The pollen of each plant usually has a unique color, so assessing pollen stores in the honeycomb helps the beekeeper determine how much food is being stored and the diversity of pollen sources by color. Inquisitive beekeepers may also develop a pollen bank by collecting pollen from the flowers they have planted and use it as a reference collection for comparing pollen stored in the honeycomb.