What's flowering for honey bees near Castro Valley, CA (San Francisco Bay Area – East Bay Hills/Valley (Castro Valley), Mediterranean climate on the eastern flank of the San Francisco Bay, transitional between coastal fog belt and inland oak-grassland), month by month — 36 local nectar and pollen sources.
Open the interactive, printable calendar →← More California bee forage calendars
| Plant | Scientific name | Category | Bloom months | Forage value |
|---|---|---|---|---|
| California Bay Laurel | Umbellularia californica | Trees | Jan–Mar | low |
| Manzanita | Arctostaphylos spp. | Shrubs & Vines | Jan–Mar | high |
| Rosemary | Salvia rosmarinus | Shrubs & Vines | Jan–Apr | medium |
| Almond | Prunus dulcis | Trees | Feb–Mar | medium |
| Willow (Arroyo/Sandbar) | Salix lasiolepis / S. exigua | Trees | Feb–Mar | high |
| Mustard (Black/Field) | Brassica nigra | Wildflowers & Weeds | Feb–Apr | high |
| Wild Radish | Raphanus sativus | Wildflowers & Weeds | Feb–May | medium |
| Miner's Lettuce | Claytonia perfoliata | Wildflowers & Weeds | Feb–Apr | low |
| Coast Live Oak | Quercus agrifolia | Trees | Mar–Apr | low |
| Bigleaf Maple | Acer macrophyllum | Trees | Mar–Apr | medium |
| Ceanothus (California Lilac) | Ceanothus spp. | Shrubs & Vines | Mar–Apr | high |
| Bur Clover | Medicago polymorpha | Clover & Legumes | Mar–May | medium |
| Vetch (Common) | Vicia sativa | Clover & Legumes | Mar–May | medium |
| Lupine (Bush/Annual) | Lupinus spp. | Clover & Legumes | Mar–May | medium |
| California Poppy | Eschscholzia californica | Wildflowers & Weeds | Mar–May | medium |
| Black Locust | Robinia pseudoacacia | Trees | Apr–May | medium |
| Blue Elderberry | Sambucus nigra ssp. caerulea | Shrubs & Vines | Apr–Jun | medium |
| Cotoneaster | Cotoneaster spp. | Shrubs & Vines | Apr–May | medium |
| Pyracantha (Firethorn) | Pyracantha spp. | Shrubs & Vines | Apr–May | medium |
| White Clover | Trifolium repens | Clover & Legumes | Apr–Jun | high |
| Common Yarrow | Achillea millefolium | Wildflowers & Weeds | Apr–Aug | low |
| California Buckeye | Aesculus californica | Trees | May–Jun | low |
| California Coffeeberry | Frangula californica | Shrubs & Vines | May–Jul | medium |
| Blackberry (Himalayan) | Rubus armeniacus | Shrubs & Vines | May–Jun | high |
| Bristly Ox-tongue adjacent legume - Sweet Clover | Melilotus albus | Clover & Legumes | May–Jul | medium |
| Bristly Ox-tongue | Helminthotheca echioides | Wildflowers & Weeds | May–Sep | medium |
| Toyon | Heteromeles arbutifolia | Shrubs & Vines | Jun–Jul | medium |
| Fennel | Foeniculum vulgare | Wildflowers & Weeds | Jun–Sep | medium |
| Star Thistle (Yellow) | Centaurea solstitialis | Wildflowers & Weeds | Jun–Sep | high |
| Telegraph Weed | Heterotheca grandiflora | Wildflowers & Weeds | Jul–Oct | medium |
| California Aster | Symphyotrichum chilense | Wildflowers & Weeds | Aug–Oct | high |
| Goldenrod (California) | Solidago californica | Wildflowers & Weeds | Aug–Oct | medium |
| Coyote Brush | Baccharis pilularis | Shrubs & Vines | Sep–Nov | high |
| Cape Honeysuckle | Tecoma capensis | Shrubs & Vines | Sep–Nov | low |
| Red Ironbark Eucalyptus | Eucalyptus sideroxylon | Trees | Oct–Jan | high |
| Blue Gum Eucalyptus | Eucalyptus globulus | Trees | Nov–Feb | high |
A bee forage bloom calendar shows which nectar and pollen plants are blooming in a given area, month by month, so beekeepers can plan colony buildup, splits, and honey harvests around the local bloom.
Every calendar starts with your zip code's specific growing region — its climate, elevation, and local ecology. From there, we use AI trained on horticultural and beekeeping knowledge to work out which nectar and pollen plants actually grow there and when they typically bloom, the same kind of judgment call an experienced local beekeeping mentor or extension agent would make, just automated so any US zip code can get a calendar in minutes instead of years of local observation. Each calendar typically covers 25-40 plants across trees, shrubs and vines, clover and legumes, and wildflowers, plus the area's named honey flows. We keep the exact generation process under wraps, but the goal is always the same: real, locally-grounded bloom timing instead of generic national averages.
The region-specific bloom timing, honey flows, and beekeeping notes are produced by an AI system drawing on general horticultural, ecological, and beekeeping knowledge, applied to your area's specific climate and geography — rather than looked up from a single official bloom-timing database, since no such nationwide dataset exists at this level of local detail.
A nectar dearth (or dearth period) is a stretch of the year when little or no medium-to-high value forage is blooming. Colonies may need supplemental feeding during a dearth to avoid starvation or robbing behavior.
A honey flow (or nectar flow) is a period when nectar is abundant enough for a colony to produce surplus honey beyond what it needs to survive, often tied to a specific major regional bloom like clover or black locust.
Bloom timing is generated from regional climate and ecology data and is intended as a general planning reference. It may not perfectly match a specific microclimate, so it's worth cross-checking against your own field observations.
Yes. Enter any US zip code to get a free, printable bee forage bloom calendar — no signup required.