Dichorisandra thyrsiflora

Dichorisandra thyrsiflora in the garden of Ian McMaugh in Sydney

This perennial plant from Brazil (ht 1.5 to 2 m) grows from thick, rhizomatous roots. It is best grown in partial shade, sheltered from hot afternoon sun in summer and protected from strong winds that can damage the tall stems. It generally blooms in autumn. The beautiful clustered flower heads are vibrant purple-blue and appear atop of spiralled, ginger-like stems of leaves, which often have purplish undersides. It needs fertile soil and reasonable moisture in the warmer months. However, once established, the plants are very drought tolerant and able to survive extended periods without rain, perhaps because of the golf ball-sized storage roots growing deeper in the soil than the rhizomes. The plant is very frost sensitive. It is best to cut the stems back after flowering. The plant is propagated by division of the rhizomes, or root or stem cuttings.

Dichorisandra thyrsiflora in the Begonia Gardens, Royal Botanic Garden, Sydney

Though known colloquially as blue ginger, it is not related to ginger plants (Zingiberaceae). It belongs instead to the Commelinaceae family of plants, which includes the various Tradescantia species. Tradescantia pallida 'Purpurea' (syn. Setcreasea purpurea, Tradescantia pallida 'Purple Heart') is a wonderful foliage plant with rich purple leaves that can provide colour all year round in shade or sun, and can provide a good companion to its cousin the blue ginger in a shaded, semi-tropical style border in Sydney gardens. Blue ginger looks stunning with Plectranthus, which are in bloom at the same time in shaded spots; and any lime-coloured foliage makes an excellent companion to its eye-catching flowers. Silver leaves - such as those of rhizome Begonia or Plectranthus argentatus - can also look wonderful with it. Blue ginger can be grown in a large pot.

Flowers in February, March, April, May.