Bees do favor blue, and the case for blue flowers for bees holds up. Honeybees, bumblebees and stingless bees are born with a pull toward short-wavelength blue, so a blue bloom in your border has something working for it. Push that claim any further and you run past the evidence. Blue does not out-draw every other color, and nobody has tested an all-blue planting against a mixed one.
"Your bees can't count," my neighbor told me, watching one bumblebee hit the same borage plant for the fourth time in a minute. That was the first spring after the border was replanted three years ago. The borage and the anchusa stayed busy for a solid hour. I checked again at noon and the bees were still working that same stretch of blue.
Bee vision colors run on a different set of parts than yours. A bee has three photoreceptors, tuned to ultraviolet, blue and green. Yours are tuned to red, green and blue, so you and the bee read the same petal in different ways. A bee also tells colors apart best near 400 nm, where the blue and ultraviolet ranges overlap. Blue petals sit close to that sweet spot.
Red is the odd one out. To a bee, a red flower often carries no color signal at all, and that is one reason bird-pollinated flowers went red and stayed there. You see a scarlet bloom and read the color as loud. A passing bumblebee reads the same petal as background, then drifts on to your next plant.
Do bees like blue? The flower record says yes. Blue turns up often among flowers that need an animal to move pollen, and blue is almost absent among wind-pollinated plants like grasses and oaks. Grass has nothing to sell you. You find color where a pollinator is there to see it.
One famous piece of research gets stretched here. Cambridge researchers built fake flowers with and without a blue halo, a tiny ridged pattern on the petal surface that scatters light. Bumblebees found the halo flowers faster than the plain ones. The pigment color was identical, and the bees learned the halo as a sign of a sugar reward. That halo is a surface structure, and you find halos in flowers that are not blue at all.
So plant blue, and plant blue as one strong band inside a wider mix. Pollinator garden blue pays off as a repeating thread through your border, because the bees in your yard are not one species with one taste. Long-tongued bumblebees want deep tubes. Small solitary bees want open faces they can land on. A border built on one color and one flower shape shuts half of your bees out.
- Spread it: Put two or three true blue plants in each part of your border instead of one clump in a corner.
- Mix shapes: Pair deep blue tubes with open flat faces so long and short tongued bees both get fed.
- Stretch the season: Pick blues that open at different times so you keep the color going in spring and again in late summer.
- Leave your yellows, whites and purples where you have them. A preference for blue is no reason to pull them.
Do not rip out your other colors on the strength of a preference this narrow. Unbroken bloom from early spring to frost feeds your bees better than any single shade can, and a hungry gap in midsummer costs you far more than a shortage of blue. Add blue where you have room, and let the rest of your border keep doing the job you planted it for.
Read the full article: 10 True Blue Flowers and Why Blue Is Rare
