Verbena hastata Alba

Verbena hastata 'Alba' is a variety of white vervain, it is a tall herbaceous perennial with an upright habit which is very hardy. Throughout the summer, the tips of its sturdy stems are covered with ramified spkies, very straight, densely filled with small white flowers with green bracts. This flowering is particularly appreciated by pollinating insects. The foliage is bright green, composed of very elongated and toothed leaves. This plant has something enchanting, combining floribundity, graphic appeal and ease of cultivation. It thrives everywhere, in any ordinary and well-drained soil, moist, fresh or occasionally dry, in the sun, and easily self-seeds in the garden.

Native to Canada and the United States, Vervain belongs to the Verbenaceae family. It colonises damp soils, riverbanks, wet meadows, and floodplains in its natural habitat. Depending on soil moisture, it can reach a height of 60 to 100 cm (24 to 39in), with a width of 50 to 60 cm (20 to 24in). It grows from a fibrous and rhizomatous stump, forming an erect, relatively narrow clump composed of occasionally branched quadrangular stems. The leaves are opposite, 10 to 13 cm (4 to 5in) long, 2.5 cm (1in) wide, lanceolate, veined, coarsely toothed, and bright green. From June to September, the stems branch out at their upper end and give rise to thin, pointed spike inflorescences, 10 to 15 cm (4 to 6in) long, composed of numerous red buds that develop into small purple flowers with five 5 mm (0.2 in) petals, resembling lilac. The buds, flowers, and bracts create a striking and splendid contrast. The flowers open from the bottom to the top. The flowering period is followed by the formation of small, hard, elongated fruits that contain seeds, which easily self-seed. Small colonies of plants, identical to the parent plant, are produced from the rhizomes.

Verbena hastata 'Alba' is perfect in a white garden and valuable for natural gardens. This perennial is remarkable at the edge of a water feature, in a moist soil, as long as it is planted en masse.  In a slightly wild scene, the tousled or well-ordered clumps of Gauras and grasses (small Miscanthus, Eragrostis, Stipa) accompany it well. Paradoxically, it also performs well in drier soil, although it will remain smaller. Its delicate, highly graphic spikes contrast with the roundness of roses, complement lavender of the same hue, and its purple stems beautifully accompany the grey or silver foliage of Artemisias, the blond or metallic blue culms of Elymus magellanicus, or the rust colour of Carex buchananii.  Verbena hastata can also be used to prepare herbal teas. The ancients attributed aphrodisiac properties to it!