`TR20` is a distinctive variety of Dianella tasmanica with a clumping habit, which is characterized by the combination of a large flower cluster with blue flowers, green foliage with red basal shoots and red green lower leaf areas, which changes to a reddish-green foliage with red leaf margins in cooler seasons, and, in the Spring, TR20 leaf colour is yellow-green with some red leaf margins and red basal shoots and red-green lower leaf areas.