Amethyst sea holly (Eryngium amethystinum)

Amethyst sea holly (Eryngium amethystinum) is a perennial plant that can grow 50cm – 1.5m tall and 10cm – 50cm wide. In this growing guide we’ll learn the cultivation details and how to plant Amethyst sea holly (Eryngium amethystinum).
This plant has several common names including: amethyst sea holly, amethyst eryngo or Italian eryngo.
This is a semi-evergreen plant that takes 2-5 years to reach full maturity.
In this article
Plant profile
Common name: amethyst sea holly, amethyst eryngo, Italian eryngo
Scientific name: Eryngium amethystinum
Plant type: Perennials
Habit: Bushy
Height: 50cm – 1.5m
Spread: 10cm – 50cm
Foliage: Semi-evergreen
Sunlight: Full Sun
Soil: Chalk, Loam, Sand
Moisture: Well drained
Garden type: Architectural, City & Courtyard Gardens, Coastal, Informal Garden, Patio & Container Garden, Rock & Gravel Garden, Wildflower meadow
Planting type: Cut Flowers, Flower borders and bedding
Other characteristics: Drought resistant
Seasonal colors
Season | Stem | Foliage | Flower | Fruit |
---|---|---|---|---|
Spring | ||||
Summer | ||||
Autumn | ||||
Winter |

How to plant Amethyst sea holly (Eryngium amethystinum) – Alvesgaspar, CC BY-SA 3.0, via Wikimedia Commons
Perennial plants are one of the largest groups of plants.
They offer color, shape, fragrance and seasonal textures. The variety is such that there are plants to suit all sizes and styles of garden.
Traditionally, perennials are grown in borders, using a wall or hedge as a backdrop to bring out all their splendor during summer.
But since most gardens are not large enough for long borders dedicated exclusively to perennials, they are usually planted in mixed borders and beds, along with shrubs, annuals, biennials, and bulbs that extend the season of interest.
How to plant
In this section we will learn how to plant Amethyst sea holly (Eryngium amethystinum), know its needs in terms of soil, watering and sun exposure.
Soil
Amethyst sea holly (Eryngium amethystinum) is not a demanding plant regarding the type of soil and can grow in chalk, loam or sand.
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The chalky soil is pale and contains chunks of calcium-rich rock. It is a fertile and well-draining soil, almost always alkaline.
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The loam soil is dark, rich in organic matter but balanced in minerals. It offers the best of all worlds, retaining enough water for the plants, but allowing excess moisture to drain away. This is the most desired type of garden soil, perfect for most plants.
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Sandy soil is light, porous and very easy to drain. It is a soil poor in organic matter and nutrients. It is composed of relatively large mineral particles that allow water to drain quickly.
It is not very sensitive to soil acidity or alkalinity and grows well in soils with pH acid, alkaline or neutral.
Regarding drainage, Eryngium amethystinum likes to grow in well drained soil.
Sunlight
Amethyst sea holly (Eryngium amethystinum) should be grown in full sun places.

Cultivation profiles – Growing Amethyst sea holly (Eryngium amethystinum) – Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons