Seasonal Pollinator Calendar
Enhancing green spaces in London where all natural pollinators can thrive, and their habitats can be enjoyed by all.
Seasonal Pollinator Calendar
Overview
Pollinators need food throughout the year, not just in summer. Providing flowering plants across seasons ensures that different species can feed during their active periods, supporting stronger and more stable populations. The gaps at the very start and end of the season are often the most critical.
Late Winter & Early Spring (January–April)
Early food sources are critical after winter. In mild years, bumblebee queens and some solitary bees may be on the wing from as early as late January — well before most garden plants flower. The earliest available sources therefore carry disproportionate importance.
Key plants:
- Hazel (Corylus avellana) — catkins from January or February, one of the very earliest pollen sources
- Snowdrops (Galanthus nivalis) — provide some early nectar on mild days, though their pollinator value is modest compared to other early flowers
- Species crocus (e.g. Crocus tommasinianus) — excellent early pollen source
- Primrose (Primula vulgaris)
- Lungwort (Pulmonaria)
- Willow catkins (Salix species) — extremely valuable, one of the best early pollen sources
- Fruit tree blossom (apple, cherry, pear) — abundant late-spring resource
Why it matters: early flowers support queen bumblebees emerging from hibernation and the first solitary bees of the year, when failure to find food can be fatal.
Early Summer (May–June)
Peak nesting and feeding season. This is when most bumblebee colonies are growing rapidly and solitary bee nesting activity is at its height. Diversity of flower type is particularly important at this stage.
Key plants:
- Foxglove (Digitalis purpurea) — biennial, excellent for long-tongued bumblebees
- Red clover (Trifolium pratense)
- Wild thyme (Thymus polytrichus)
- Alliums
- Catmint (Nepeta species)
- Hawthorn blossom (Crataegus monogyna) — extremely valuable for a wide range of insects
Late Summer (July–August)
Pollinator activity remains high and forage needs are at their peak. This is the busiest period for most species.
Key plants:
- Lavender (Lavandula angustifolia)
- Common knapweed (Centaurea nigra)
- Scabious (Knautia or Scabiosa species)
- Verbena bonariensis
- Wild marjoram (Origanum vulgare)
Autumn (September–October)
Late-season nectar is essential — bumblebee queens preparing to hibernate and solitary bees completing their nesting must build sufficient energy reserves before winter begins.
Key plants:
- Ivy (Hedera helix) — one of the most important late-season plants in the UK, providing nectar and pollen when almost nothing else is available
- Sedum / ice plant (Hylotelephium spectabile)
- Asters (including Michaelmas daisy, Symphyotrichum novi-belgii) — reliably late-flowering and attractive to a range of species
Winter (November–January)
Most pollinators are inactive during the coldest months. Bumblebee queens hibernate underground; solitary bees overwinter as eggs, larvae or pupae inside nest cells. However, on mild winter days — particularly in southern England — bumblebee queens and some solitary species may venture out briefly and need forage if they do. Winter-flowering shrubs such as mahonia, sarcococca and winter heather can provide valuable resources on these occasions.
Support actions during winter:
- Leave plant stems standing through winter — hollow stems provide nesting sites and hibernation shelter
- Keep leaf piles in undisturbed corners — valuable overwintering habitat for many invertebrates
- Avoid heavy pruning until late winter or early spring when temperatures are reliably above freezing
- Protect nesting sites — avoid disturbing soil, log piles and bee hotels
Key Principle
The best planting scheme ensures something is in flower in every month of the year. The gaps at the extremes of the season — late winter and late autumn — are where additional planting has the greatest impact.