Tradescantia andersoniana Zwanenburg Blue - Spiderwort

Tradescantia x andersoniana 'Zwanenburg Blue' is a vigorous and beautifully coloured Virginia spiderwort, which charms with its intensely blue flowers, slightly violet, and subtly enhanced with yellow stamens. They renew themselves above a beautiful clump of narrow, pointed leaves for long weeks in summer, if the soil remains moist. Hardy and very easy to grow, this robust perennial is perfect for bringing a little colour and luxuriance to the partially shaded beds and borders of the garden, or along the edge of a pond. It also grows very well in pots.

'Zwanenburg Blue' is a horticultural hybrid of Tradescantia  whose origins are found in the two Americas (Tradescantia ohiensis, T.subaspera, T virginiana). All these plants belong to the commelinaceae family. It is a herbaceous perennial whose above-ground vegetation emerges in spring and disappears in winter in a dense clump about 50 cm (20in) high, spreading about 50 cm (20in). Its dark green glossy foliage resembles grasses, consisting of simple, long and narrow, pointed, arched leaves, sheathed on a tubular stem. Flowering begins in June and lasts all summer in moist soil with flat, triangular flowers, composed of 3 wide petals, with contrasting yellow stamens, borne on long purplish peduncles. They are simple and original and bloom in pairs carried in small clusters or terminal cymes at the top of stiff floral stems. Each flower only 'lives' for a few hours, but they are constantly renewed above the foliage.

You can plant Tradescantia andersoniana 'Zwanenburg Blue' in rich, moist to wet soil. This plant prefers this type of situation, and will show its full potential in a partially shaded exposure that will highlight the colour of the flowers. In full sun, regular and abundant watering will be essential. In a moist rockery, at the foot of a shaded wall, in a woodland or even in borders, its flowering will illuminate all the small shaded areas. This perennial will thrive on the banks of streams or ponds, with Carex, tiarelles, Persicaria, Primula bulleyana or Ophiopogon japonicus. It also grows well in pots, in partial shade, with careful watering.