Sea holly
A steel-blue spiny umbellifer that looks like a thistle and is in fact a relative of the carrot, and one of the best late-summer nectar plants in a dry border. Its tiny flowers sit in a dense cone surrounded by a spiny metallic ruff, and they are completely open — which makes it usable by the small solitary bees, wasps and hoverflies that deep-flowered plants exclude.
Value to bees
- Nectar
- Very high
- Pollen
- High
- As a honey crop
- Feeds the colony but rarely yields a surplus
- Which bees, and why
- An exceptionally broad visitor list — honey bees, bumblebees, solitary bees, hoverflies, wasps and beetles all use it, because there is nothing hidden. It is one of the best plants a border can hold for the small and short-tongued insects most planting ignores.
Tiny fully open florets with completely exposed nectar. As accessible as forage gets, alongside the other umbellifers.
- Worth knowing
- Very high for both, in an entirely accessible form, at a point when many borders have gone over.
Flowering
- In flower
- July to September (northern hemisphere)
Six to ten weeks in high summer, and the heads remain ornamental long after the flowers finish.
- When nectar flows
- Generous and completely exposed, which is what makes it usable by so wide a range of insects.
- Year-to-year variation
- Very dependable including in drought. Not a crop.
Growing it
- Conditions
- Full sun and very sharp drainage. Most species have a long taproot and resent being moved.
- Size
- 45-90 cm.
- Native range
- Europe and the Mediterranean, with several species from coastal sand and dry grassland.
- Suits
- Small gardens, Large gardens, Containers and window boxes, Meadow or wildflower area
- Plant it where it is to stay. The taproot means established plants transplant badly.
- Leave the seed heads over winter — they are among the best frost subjects in a garden.
- Sea holly proper, Eryngium maritimum, is a protected coastal native in Britain and should never be dug from the wild; the garden species are unrelated to that concern.
What it looks like
Rigid branching stems with spiny holly-like leaves, carrying cone-shaped flower heads of tiny florets surrounded by a stiff spiny collar, the whole plant often flushed metallic silver-blue.
Sources
- Field Guide to the Bees of Great Britain and Ireland — Bloomsbury (2015) · Field guide
- HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
How sources are selected and weighted is set out in the sources and evidence policy.
Guides covering this plant
- How to make a garden genuinely useful to beesMost bee-friendly advice covers flowers in June, which is the one thing bees are least short of. The gaps are at the ends of the year — and half the problem is not flowers at all.
- Why botanical family is the most useful thing to know about a bee plantCorolla depth, floret arrangement and whether nectar is exposed are inherited traits. Learn a family and you can predict a plant nobody has catalogued.
- A Mediterranean bee gardenThe one climate where the bee-friendly planting and the drought-tolerant planting are the same list. The Mediterranean gap is not winter — it is the dead of summer, and the plants that solve it are mostly herbs.
Tools for planning planting
- Flowering calendar
What should I plant so that something is always in flower for bees?
- Bee-friendly garden planner
What should I plant in the space I actually have?
- Plant recommendation tool
Which plant fills this specific gap?