Honey bee plants of Pacific Northwest Lowlands
Here, near the north end of Lake Washington, WA, USA, my bees start collecting pollen in January.
They work in the warm afternoons in February.
Serious foraging begins in March.
In a good year, they collect lots of nectar and pollen from maples and cherries throughout April.
Flow continues in May. Do not let them swarm before the blackberry!
In a good year, the blackberry flow starts in mid June, as colonies reach the maximum strength.
Things slow down after the blackberry, but here are some good July bloomers.
At the height of summer drought in August, bees find forage in wetlands.
English ivy begins to bloom in September.
Bees work on the ivy throughout October, and also visit some garden flowers.
Foraging hours are short in November, but they may find some fall bloomers in addition to the ivy.
I think they take a short brood break in December. I seldom see them carrying pollen.
Where did my bees get those pollen loads?
Honey bees bringing in pollen loads, in a few different shades of yellow (Apr 12, 2019).
Pollen chunks honey bees dropped in a beehive*
*Photos show a corrugated plastic board, which was inserted under 1/8" hardware cloth at the hive bottom.This kind of hive setting is primarily for monitoring varroa mite infestations.
Observing bee pollen under microscope
1. Place a chunk of pollen on a slide glass.
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2. Drop small amount of glycerin.
3. Place a coverglass, lightly smear the pollen chunk, and immediately* take a photo.
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*Because I do not make permanent slides that require fixing agents, I take a photo within a half minute of smearing pollen.
I used an inverted microscope (800x), connected to a computer
The most common pollen species found in my beehives
I have conducted a systematic analysis of pollen samples from my beehives, covering the years 2018 to 2023 and totaling 25,784 specimens. The identification of pollen sources was carried out by considering the current bloom status, pollen color, and microscopic images (cross-referenced with images in my flower pollen library, which were directly collected from each plant species). The top 20 identified pollen sources are as follows:
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Genus Hedera - 18.5%, most likely English ivy.
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Genus Rubus - 11.4%, most likely Himalayan blackberry.
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Genus Prunus (excluding cherry laurel) - 8.8%, most likely cherry plum, sweet cherry, bitter cherry, and Japanese cherry.
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Genus Acer (maple) - 7.3%, most likely bigleaf maple, vine maple, and red maple.
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Genus Oenothera - 3.1%, most likely evening primrose.
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Subfamily Cichorioideae - 3.0%, most likely Dandelion, cat's ear, and hawksbeard.
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Genus Salix - 2.5%, most likely Scouter's willow, Sitka willow, and Pacific willow.
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Genus Hydrangea - 2.3%, most likely oak leaf hydrangea and panicled hydrangea.
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Genus Reynoutria - 2.3%, most likely Japanese knotweed.
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Genus Crataegus - 2.2%, most likely common hawthorn.
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Genus Magnolia (during summer) - 2.2%, most likely southern magnolia.
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Liriodendron tulipifera - 2.1%, tulip poplar
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Genus Camellia - 2.0%, mostly spring blooming common camellia and hybrids.
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Genus Castanea - 2.0%, most likely European chestnut.
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Genus Impatiens - 1.9%, most likely jewelweed.
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Genus Aralia - 1.6%, Japanese angelica tree and/or devil's walking stick.
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Genus Malus - 1.2%, orchard apple and flowering crabapple.
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Prunus laurocerasus - 1.1%, English cherry laurel.
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Genus Trifolium - 1.1%, most likely Dutch white clover.
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Fuchsia magellanica - 1.1%, hardy fuchsia.
Honey bees are not the only visitors to flowers
These bees, fluffier and rounder than honey bees, are bumble bees. Their distinct appearance makes them relatively easy to identify, making them a good starting point for getting acquainted with native pollinators.
Alongside bumble bees, I've been working on identifying different bees that visit my flower garden. Bugguide.net has proven to be a valuable resource in this endeavor.
Bees on the native flowers of Pacific Northwest lowlands
Let's explore to discover our native flowers, which might not be as visually striking as exotic species or garden hybrids. Yet, if you are situated amidst natural areas, these flowers could serve as primary sources of nectar and pollen for your honey bees, as well as various native pollinators like bumble bees. Even in urban settings, native plants and nativars (cultivated varieties of native plants) are commonly employed in landscaping. Their adaptation to our wet-winter, dry-summer climate allows them to flourish in gardens with minimal care.
Oemleria cerasiformis (osoberry, Indian plum) & Apis mellifera (honey bee)
A sizable deciduous shrub commonly discovered in open woods. In most years, it is the first native nectar source in Pacific Northwest lowlands. I planted one in a partially sunny spot in my garden, which turned out to be a male plant (see the yellowish pollen on the honey bee).
Acer macrophyllum (bigleaf maple) & Bombus flavifrons (yellow-head bumble bee), queen
Undoubtedly one of the most substantial native nectar sources in spring, its towering height poses a challenge in spotting bees on its flowers. In this particular instance, I positioned myself at the edge of a small cliff to closely inspect a high branch.
Chamaenerion angustifolium (fireweed) & Bombus flavifrons (yellow-head bumble bee), male
A perennial wildflower, standing at a height of 2-5 ft, boasts lance-shaped leaves and vibrant deep-pink flowers. Thriving from sea level to subalpine regions, I deadhead mine to ensure the flowers persist until mid-October.
