Collection of plants for a dry summer flowerbed

The collection consists of:

- x 1 Cardoon, Cynara cardunculus: a remarkable perennial or biennial in ornamental gardens. Its superb artichoke-like, bluish pink flowers emerge at a height of 1.50 m, between June and August. The plant forms a clump of large, grey, velvety leaves, decorative like wrought ironwork, covering about one square metre. It remains evergreen in winter. The cardoon is a centrepiece in itself, at the heart of the bed. Hardiness: -12 °C

- x 1 Spiny Bear's Breeches, Acanthus spinosus: a majestic perennial plant, reaching a height of 1 m when in bloom. It develops large, spiny, highly decorative, deeply cut, shiny dark green leaves, and offers a summer flowering with spectacular spikes adorned with white flowers and spiny pink bracts. Moderately hardy, it perishes below -10 °C.

- x 1 Purple Rockrose, Cistus x purpureus: a Mediterranean evergreen shrub, about 1 m in all directions. It is covered between April and June, depending on the climate, with flowers resembling dark pink dog roses, 6-7 cm in size, adorned with purple-red spots. Its evergreen foliage is fragrant in hot weather. Hardiness: to -12 °C in rocky soil.

- x 1 Hairy Chervil, Chaerophyllum hirsutum: a graceful and lesser-known perennial, this beautiful umbelliferous plant forms a clump of finely cut, velvety foliage that emits a pleasant apple scent. It forms a well-branched bushy clump of 80 cm, adorned with flattened umbels, 8 cm in diameter, in a mauve pink colour. The plant blooms between May and June. It is less drought-resistant than the other three.

The cardoon, due to its stature, is logically planted in the centre of the bed. The acanthus and the rockrose will be placed in front, with 1 m between each plant. Ideally, they should be planted on a mound, especially in areas with borderline hardiness. In this case, the rockrose will be placed at the top of the mound, the cardoon below, the acanthus slightly lower, and the chervil at the bottom of the mound. In very dry soil, it is preferable to replace this chervil with an evergreen sage 'Icing Sugar' or a pink-flowering grass like Muhlenbergia capillaris.

Three plants in this collection are moderately hardy but very resistant to drought. The chervil, on the other hand, is insensitive to cold but prefers slightly moister soils. This selection of 4 plants is therefore more suitable for a garden that is not too arid in summer.