PlantsFlowers

Sea Holly

Sea Holly (Eryngium planum)
Le.Loup.Gris · CC BY-SA 3.0
Sea Holly in flower
In flower · (c) Denis Ibaev, some rights reserved (CC BY) · CC BY

Eryngium planum

Zone 6a garden plant. Hardy through a Chicago winter unless the note says to pot it.

Blue thistles that like a mean, sunny spot

EasyFlowers
Light
Full sun
Moisture
Dry
Mature size
2–3 ft
Spacing
1 ft
Bloom or harvest
Flowers Jun–Aug
How it spreads
Taproot
What to buy
A small pot. Don’t break the root.
When to plant
May

In the design

Dry sun. Wet clay in winter is what kills it, not the cold. Not rattlesnake master, which is the native one to use if the brief is a prairie.

Plants that share this spot

More in this group

Reference details
Conservatism value
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Wetland indicator
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