Designing with Eryngium bourgatii
text and photography byCAROL KLEIN
Gardening is all about relationships—between the garden and its surroundings, between hard and soft landscaping, and between plant and plant. Putting plants together writes garden sentences, and the sentences tell stories.
In this series we look at several stalwart herbaceous plants and put them together with other characters to create different pictures. All are versatile, straightforward individuals, none more so than this issue’s choice—Eryngium bourgatii.
With its large, decorative bracts, E. bourgatii (USDA Zones 4-9) is one of the best of the sea hollies. It occurs in several European mountain ranges, as well as in Turkey and North Africa. Although it experiences hot summer temperatures in its native haunts, since it often grows at high elevations it is also able to endure low winter temperatures.
Careful selection has resulted in several remarkable varieties being offered to gardeners. The most eye-catching forms are those in which stems, bracts, and flowers are suffused with blue. Here at Glebe Cottage, we have been selecting plants for several years and now have a blue strain and a purple strain, both of which have broad bracts and rich color.
For sources of plants featured in this article, turn to page 76.
(1) Eryngium bourgatii ‘Glebe Violet’; (2) Actaea (Cimicifuga) simplex Atropurpurea Group; (3) Francoa ramosa ‘Rogerson’s Form’; (4) Thalictrum decorum
The depth of color of the bugbane’s almost black leaves and the rich green, crinkled rosettes of the francoa provide a shadowy backdrop against which the interplay between the shapes and colors of the flowers unfolds. There is contrast, too, between the flower forms, with the bold, spiky stars of the eryngium wending their way among the other plants; the tightly packed ramrods of the francoa interjecting their abrupt verticals; and the winsome wands of the thalictrum hovering over the scene. The eryngium provides sparkle both from its bracts and its leaves, which are deeply marbled with white.
The tall, dark stems of the exceptionally striking Actaea (Cimicifuga) simplex Atropurpurea Group (Zones 3-9) ascend to about six feet. The beadlike buds burst to reveal pure white flowers, each a miniature collection of petals and stamens—with a sweet, delicate perfume. As a foliage plant, this bugbane is unsurpassed: its broad, cut leaves of deepest maroon look dapper from spring to fall.
Francoa ramosa ‘Rogerson’s Form’ (Zones 8-10) is a favorite in my garden, making rich verdant clumps and lifting the tone wherever it is planted. If you garden in a cold climate, you can ensure next year’s plants by taking short basal cuttings at any time during the growing season; they will grow apace when planted out. Another alternative is to grow them as pot plants.
Native to western China, Thalictrum decorum (Zones 5-10) grows on hillsides shrouded in mist. It needs ample moisture but will not tolerate stagnant conditions. Everything about it is dainty, from its tiny maidenhair foliage to each pixie-hat flower with pendulous, creamy anthers. It is very late to show its head in the spring, so usually avoids the worst frosts.
(1) Eryngium bourgatii ‘Glebe Blue’; (2) Aeonium ‘Zwartkop’; (3) Cerinthe major ‘Purpurascens’; (4) Geranium wallichianum ‘Buxton’s Variety’; (5) Hakonechloa macra ‘Aureola’
Growing perennials in containers is an immensely useful practice, allowing you to change them around easily or fill embarrassing gaps in the border. Some tap-rooted species are unhappy in a pot, but eryngiums fare well in containers, provided they are deep and a rich, loam-based compost is used.
The major players here are the eryngium and the hakonechloa, the sea holly’s purple, spiky stars forming the perfect counterpoint to the graceful, fountainlike growth of the grass. Yellow and blue are always easy on the eye. The blue geranium and the cerinthe broaden the blue theme from soft lilac-blue to marine hues. Their forms are different but work well together: the low, marbled foliage of the geranium scrambles over the edges of pots, while the cerinthe pushes up vertically, animal-like, with rearing heads containing its strange, indigo flowers, whose darkness is emphasized by the aeonium. There is an overall feel of the circus ring, with each act doing its own thing yet complementing the others, all part of the same orchestrated performance.
Nothing can beat Aeonium ‘Zwartkop’ (Zone 10) for high drama. Its perfect symmetry has caused many an onlooker to ponder the meaning of the universe. Pot culture suits it: it can be moved around to make new pictures wherever a bold statement is needed, and then brought indoors for the winter.
Cerinthe major ‘Purpurascens’ (hardy annual) has become a hit plant, thanks to its subtle aquatic coloring. A Mediterranean member of the borage family, it brings an exotic touch to run-of-the-mill plantings. In frost-free gardens it may survive for years and will self-seed prolifically.
The irresistible Geranium wallichianum ‘Buxton’s Variety’ (Zones 6-10) is particularly useful because its lilac-blue flowers, with their distinctive white centers, only start to appear toward the end of the summer. By then the reddish stems have stretched out, bearing their exquisitely marbled leaves.
The unmistakably Japanese Hakonechloa macra ‘Aureola’ (Zones 5-9) has all the dignity of a painting on silk. The narrow stripes of green running through the golden leaves emphasize the linearity of the blades. There is enough green in the leaves to keep them from scorching, but it is best kept out of really hot sun.
(1) Eryngium bourgatii ‘Glebe Violet’; (2) Aster xfrikartii ‘Monch’; (3) Campanula trachelium; (4) Eryngium giganteunr; (5) Scabiosa ochroleuca
Lashings of blue and green form the backbone of this cottagey mixture. There are hints of yellow from the scabious, which will be magnified later by rudbeckias and patrinias. Growing in a narrow south-facing bed at the top of a low wall, this carefree melee brings the informal spirit of the garden right up to the cottage. Most of the plants have small leaves and branching stems, which adds to the meadowy feel. The big daisies of Aster xfrikartii ‘Monch’ are just beginning their three-month show, and Campanula trachelium interjects its warm blue bells into the proceedings. There are heads of Agapanthus ‘Midnight Blue’ here and there and a sprinkling of Eryngium giganteum, Miss Willmott’s ghost.
On everybody’s 10-best-plants list, Aster xfrikartii ‘Monch’ (Zones 5-10) is possibly the most beautiful daisy around. Its clear lilac-blue flowers are a perfect match for the eryngium. It takes a little time to get established, but once it does, lives happily for a long time in the same position. Best propagated by short basal cuttings in the spring, it hates to be moved and does not divide easily.
Campanula trachelium (Zones 3-10), the nettle-leaved bellflower, is a stalwart plant that self-seeds prolifically. Never a nuisance (seedlings can be removed or transplanted at an early age), it has a genius for putting itself in just the right place. Its blue is tremendously deep and the best plants also sport crimson stems.
I would hate to be without Eryngium giganteum (Zones 5-10; biennial). Its yard-tall stems, bedecked with silver, wide-ruffed flowers, are a delight from midsummer onward. The first-year rosettes of leathery, evergreen leaves seem to tough out cold winters, provided drainage is sharp.
Scabiosa ochroleuca (Zones 5-10) is a favorite with butterflies and hoverflies—so important if you are gardening organically. Its dainty, pale lemon, pincushion flowers are produced by the hundred. When the petals fall, small, globose seed heads remain.
(1) Eryngium bourgatii ‘Glebe Blue’; (2) Agapanthus ‘Midnight Blue’; (3) Calendula officinalis
Wham: the simplest associations can be the most dynamic. The contrast between the clustered stars of the eryngium’s flowerheads, the rich ultramarine globes of the agapanthus, and the scattered vivid discs of the marigold creates major zing. The agapanthus are at their best for six weeks at the most, but since the sea holly maintains its color for months, the excitement can be maintained if the pot marigold is assiduously deadheaded. Although it is an annual, it will self-sow if a few seed heads are allowed to ripen.
Agapanthus ‘Midnight Blue’ (Zones 6/7-10) is one of the most desirable Nile lilies. It has fine foliage, stained blue at the base, and flowers prolifically. It is deciduous, and hardy to 5°F. In borderline areas, its crown should be covered for the winter with six inches of soil; alternatively, plants can be lifted and potted up in a loam-based mixture.
The flowers of Calendula officinalis (hardy annual) were used to flavor soups and stews in Elizabethan times. If seedlings are thinned out, each plant will grow to about 18 inches, branching in all directions with a wealth of flowers until the frost. Although there are new hybrids galore with very double flowers, quilled petals, or strange colors. I like my marigolds single and orange.
(1) Eryngium bourgatii ‘Glebe Blue’; (2) Achillea ‘Anthea’ and Achillea ‘Credo’; (3) Gladiolus papilio Purpureoauratus Group; (4) Leymus arenarius
Again, a limited palette gives happy results. Yellow and blue predominate, but here they are joined by gray and glaucous foliage, which creates a dry seaside or mountainside feel. The eryngium is the star of the show, but it would be a lesser being without help from its friends. Behind it, a bold clump of Leymus arenarius makes a collection of close verticals, echoed here and there by the swords of the gladiolus. Both are glaucous. As a backdrop, Elaeagnus ‘Quicksilver’ cascades, making a nice counterpoint to the upright grass. Platelike heads of pale yellow achilleas concentrate one’s vision in the center of the arrangement, where the sea holly’s blue sparkles against the grays and lemons that surround it.
Alan Bloom, the renowned English nurseryman, is responsible for Achillea ‘Anthea’ (Zones 3-10), with ghostly gray foliage and palest lemon flowers. Achillea ‘Credo’ (Zones 3-10) is the work of Ernst Pagels, a German nurseryman whose perennials and grasses have won him wide acclaim. It is the taller of the two, with more green in its ferny foliage and deeper lemon flowers.
Gladiolus papilio Purpureoauratus Group (Zones 7-10) is sophistication on a stem. A colonizing plant, it will soon occupy a much bigger area than was ever envisaged. Most gardeners don’t mind, since it is easy to remove should it overstep the mark. As the stems fatten up, there is general excitement at the prospect of the first emergence of its mysterious, hooded flowers in subtle purple gray with lemon-yellow splodges on the lower petals. In cold areas it can be lifted and potted up for the winter.
Leymus arenarius (Zones 4-9) can be a thug. Here it is planted in its pot to curb its colonizing ambitions. It is a seaside grass, good at retaining sandy soil on a slope. It has high ornamental value for its almost blue blades and in a warm position produces wheaten seed heads. H