I love this unusual shrub, supposedly hardy only to zone 7b, but which has thrived for three years in my garden here in NY. It is a relatively new introduction from China, and I have never seen one growing in our area except for my plant. I think my plant came from Heronswood, when it was still a real nursery. Plant Delights also carries it. It is a dieback shrub, resprouting from the base after winter and making rapid growth up to 5 feet or so by the time it blooms in October. Sometimes buds a few inches above ground level on the previous years branches will also break and grow in spring. The foliage is neat and attractive. The flowers are not individually very showy, but the graceful drooping spikes create a unique and lovely effect. I especially liked the combo I created of Rostrincula and the humble dog fennel (Eupatorium capillare) with its finely divided foliage as a perfect foil for the pendant purplish inflorescences. It can be propagated from cuttings taken in summer.
The dog fennel is a southern native, easily rooted from cuttings gathered in summer. My plants came from cuttings I collected in the Charlotte NC area and brought back home. It is a common field weed in the south, but flowers too late here most seasons to set ripe seed so it is not able to establish itself in nature north of Virginia, despite being quite cold hardy. One probably also needs more than one clone to set viable seed, as is often the case in its family, the Asteraceae. It can get huge, as the pics attest, but I would not be without its billowing masses of lacy foliage in the summer and fall garden.