Eryngiums, better known as Sea Hollies are really great architectural plants for the garden and they’re easy to grow too. Thriving in even poor soils they will reward you with masses of long lasting thistle like heads of flowers in summer. These are much loved by flower arrangers for adding structure to arrangements. If they sound a little prickly for you, don’t worry. They’ll go really well with softer, cottage garden plants like Astilbes or even in a seaside garden or with architectural plants like palms.
It is best to grow them in a well-drained, fairly fertile spot, they don’t mind too much if it gets dry. A strong root system will anchor them firmly in to even the lightest soils. The only problem you might come across is if they get too wet in winter, which can lead to them rotting off, but this, is rarely a problem. Give them a good mulch in the Spring and Autumn and plant them in a sunny position and you’ll see the best they have to offer.
Eryngium giganteum "Miss Willmott’s Ghost" is a bi-annual so short lived variety but it always comes up here each year. A sturdy variety with wonderful silvery bracts surrounding paler flower heads it grows up to about 32" (80cm) tall. Flowering over a long period. Eryngium varifolium is another good variety with clumps of evergreen, small heart shaped, white veined, green leaves.
Growing to a maximum height of 18-24" (45-60cm), highly ornamental spiky flowers are produced.
Erygium planum, a favourite variety of many gardeners gets up to three feet (90cm) tall with masses of majestic blue flower heads and spiky stems. The leaves are attractive dark green, heart shaped and evergreen. Planted en-mass this variety produces a dramatic, classy show. If your looking for something a bit different you could try Eryingium agavifolium, this rarity forms large clumps of spiky yucca like leaves and has tall stems with green flower heads, quite unusual.
Another favourite of mine alongside Eryngium agavifolium, is Eryngium maritimum , the true Sea Holly.
This plant is actually a native of these shores where it clings to rock crevices right besides the sea. It has grey-blue spiny leaves, which are rather thick and typical Eryngium ‘thimbles’ as flowers, which are again a bluey colour.
The latter species will need very sharp drainage in full sun and are very cold hardy.
All Sea Hollies can be purchased from most garden centres and nurseries or propagated from fresh seed
© 2000 Chris Bonnett - Gardening Express