Honeybee NectarFlow-Black Locust Trees

Black Locust bloom

Planting peas by St Patrick’s Day is an American farming tradition that goes way back and I can remember my father relating this age-old practice. He spent his childhood on a farm and knew all the old-time ways. I didn’t have any beekeeping relatives, but if I had I am sure they would have told me to super my hives (adding extra storage boxes for nectar) when the Black Locust blooms. Beekeepers, like farmers, still look outside in the natural world to gauge how to manage their honey crop.

The lower large box is a brood box, where the queen lays eggs, and the upper boxes are supers

The Black Locust tree, Robinia pseudoacacia, is famous for producing a fruity and fragrant light green honey. Native to the Eastern United State, I always look for this tree to bloom in the spring as a sign that “honeyflow” or “nectarflow” is starting for my honeybees.

Honeybees love native Black Cherries that bloom at the same time

An abundance of nectar sources blooming in profusion means a nectarflow is starting with the bees collecting excess nectar. When bees bring in more nectar than they need or can use, that is when a beekeeper rejoices and can remove the extra stored honey for themselves. Contrary to widely held opinion, bees only produce excess honey in the early spring or occasionally in late summer, and beekeepers harvest in July for much of the United States. In southern states, where native flowering is much more abundant over a longer time period, beekeepers can get two harvests.

Honeybee nectaring from a late nectar source-Dahlia

The Black Locust tree is native to eastern and southeastern North America, but has spread throughout the United States and much of Canada and can be invasive. They grow quickly on roadsides and fields and now the creamy heavily scented branches are hanging heavy over a road that I travel every day. Most people would zip by and not pay any attention at all to these beautiful trees as the blooms are usually high up in the canopy. But I stop and whip out my camera to zoom in on these beautiful blossoms!

The flower racemes pull down the branches of the tree

Last year, because of the fickle weather, Black Locust didn’t bloom in the great abundance that I see this year, so I am hoping for a good honey harvest. But this spring we have had lots of spells of rainy cold days when the bees can’t fly and that might cut short the nectar flow.

A warm and sunny spell during honey flow means that a strong hive can fill a honey super with nectar in two days! Remember…. that is nectar. Ripe honey has had its water fraction reduced greatly by bees fanning nectar to increase water evaporation to produce the sugar concentration necessary to produce honey. Once honey is ready, the bees cap over the top with wax.

Ripe honey cells are capped by wax in the upper left hand side; on the lower right are growing brood

Blooming for about 10 days between April and June, here in the mid-Atlantic, the racemes of blooms of Black Locust opened in early May. Even before the flowers opened, the bees started collecting pollen from the tree which they need to feed their growing brood or larvae. Worker bees will flock to the flowers for the abundance of nectar that they produce, once the days turn warm and sunny and browse from other flowering trees and vegetation, like the Black Cherry. With the onset of blooming, bees start producing wax which requires several times more nectar than honey. And bees need honeycomb built first before storing nectar. The purpose of a spring flow, for the bees, is to provide food for the rest of the year, not honey for the beekeeper!

The racemes of the Black Locust flowers hang down 8 inches

After this big burst of native bloom, there is usually a summer dearth until goldenrod, asters, and other late bloomers appear. That is why gardeners should plant summer bloomers to supplement their diet. Plant those Zinnias, Sunflowers, etc. Go to Plant These For The Bees.

Plant These For The Bees poster available at TheGardenDiaries Etsy Shop

Asters are an important late season nectar source for all pollinators

Healthy hives may produce queen cells in preparation for swarming, as the spring nectarflow builds; their normal method of making new colonies. The old queen and a large swarm of bees will go off and begin a new hive. See Swarming of the Bees.

Producing more queens prior to swarming
Bee swarm in my backyard tree

Interesting and Surprising Facts About Black Locust

  • Abraham Lincoln, as a young man, built up his muscles splitting logs from Black Locust trees for firewood and fence posts

  • Extremely hard wood, one of the hardest and rot resistant in North America, the wood is valuable for floors, boats, fence posts, and furniture

  • A member of the Fabaceae (pea family), the tree has nodules of nitrogen-fixing bacteria on its roots which make it an excellent species for re-vegetating poor or damaged soils

  • Newly cut wood has an offensive odor which disappears with time

  • The flowers are eaten in Japan, France, and Italy, battered and fried as beignets or in tempura

  • The bark, wood, and leaves are toxic to livestock and humans, so farmers remove them from their fields

  • Black Locust blooms along with privet, multi-flora, blackberries, honeysuckle, and other native vegetation to produce the abundance of available nectar for pollinators; so even invasives play a role in supporting pollinators

  • Black locust is an interesting example of how one plant is considered an invasive species even on the same continent it is native to

  • Racemes of flowers can hang 4-8 inches long and intensely fragrant smelling like an orange tree

  • Highly tolerant of pollution, the tree is planted in Europe and produces the acclaimed ‘Acacia Honey’

  • One of the best woods for burning in wood stove, it has little or no flame and can burn when wet, burning at a comparable temperature as coal

  • Compounds in the heartwood allow the wood to last over 100 years in soil