Bottlebrush Red ClusterCallistemon spp. This unique shrub produces bottle brush like bright red blooms and attracts hummingbirds! Water Requirements: Low to moderate water needs. Drought tolerant once established. Soil: Rich, well draining soils. Growth Rate: Moderate. Bloom Time: Year round. Temperature: Warm and humid, will not survive freezes. Pruning: Extensive pruning should be done in late winter. Toxicity: Not toxic.