Oilseed rape

Brassica napusBrassicaceaeAnnual

The yellow fields that cover much of northern Europe and the Canadian prairies in spring, and the largest single early honey flow in temperate agriculture. Oilseed rape transformed European beekeeping from the 1970s onwards: it arrives enormously early, yields enormously heavily, and produces a honey that sets so fast it can granulate in the comb. It is also the clearest illustration of the monoculture problem — a landscape that offers everything for three weeks and almost nothing afterwards.

Value to bees

Nectar
Very high
Pollen
Very high
As a honey crop
Major honey crop — yields a surplus in good years
Which bees, and why
Worked by everything, and honey bee colonies can build with extraordinary speed on it. The problem is the cliff edge: when a hundred hectares of rape finishes within a few days, a landscape that was feeding a colony superbly offers nothing at all, and colonies can go from surplus to starvation inside a fortnight. This is the practical face of the forage-gap argument.

Open four-petalled flowers with fully accessible nectar — usable by short-tongued bees, hoverflies and beetles alike.

Worth knowing
Top-rated for both nectar and pollen, and delivered at exactly the moment colonies are expanding fastest in spring. Its faults are entirely about what comes after.

Flowering

In flower
April to June (northern hemisphere)

Winter-sown crops flower from April, spring-sown into June. Three to four weeks per field, and the fields are large.

When nectar flows
Secretes freely in cool conditions when many plants will not, which is a genuine part of its value — it flows on days too cool for lime or clover.
Year-to-year variation
More reliable than most major flows, being a planted crop of known area. The variable is acreage rather than weather: rape acreage has fallen sharply in parts of Europe following neonicotinoid restrictions and flea beetle pressure, and the honey has fallen with it.

What it does to the honey

Rape nectar produces the highest glucose share of any common honey, which is why rapeseed honey sets within weeks and sometimes within days, and why it is the standard base for commercial soft-set honey. It gives very little flavour — a faint brassica note when fresh, fading to clean blandness.

Growing it

Conditions
Field agriculture: fertile soil, full sun, and a rotation slot.
Size
80-150 cm.
Native range
A cultigen, arising as a hybrid of turnip and cabbage and known only in cultivation. Grown across Europe, Canada, China, India and Australia.
Suits
Farm scale
  • Not a garden plant. It appears here because it is one of the most consequential bee plants in the temperate world, not because anyone should sow it in a border.
  • Where rape dominates a landscape, planting or leaving field-margin forage that flowers from June onwards does more for bees than adding more rape ever could.

What it looks like

A tall annual or biennial crop with blue-green lobed leaves and dense heads of four-petalled bright yellow flowers, followed by slender seed pods. Winter and spring sown varieties flower several weeks apart.

Sources

  • HoneyHQ editorial synthesisHEKNO Ltd · HoneyHQ synthesis
  • Assessment Report on Pollinators, Pollination and Food ProductionIntergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic review Link

How sources are selected and weighted is set out in the sources and evidence policy.

Guides covering this plant

Tools for planning planting

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