PlantFiles: Derwent Speedwell
Derwentia derwentiana

This is an attractive Australian speedwell, growing in moist forests and particularly subalpine habitats up the East coast of Australia. The plant has a woody perennial rootstock from which multiple stems arise each spring, reaching to 1.8 metres tall, and bearing spikes of white or very pale blue or lilac flowers. In subalpine areas it can grow in large numbers along roadsides.
I have once successfully grown it from seed for a revegetation project, but have not yet established one in my garden. The seed is very small and not easily collected. possibly bagging a flower spike as the seed is nearly ripe would be the most effective method.