Once established, Western Ironweed can colonize by rhizomes. Great for gardens with lots of space, otherwise it can take over small areas. Tough, drought tolerant. Few seeds are fertile, so sow thickly when soil temperature is warm. May also propagate by root division and softwood tip cuttings. Leave stems till spring to provide nesting habitat for tunnel-nesting bees. Needs well-drained conditions. Propagation: Seed, Root division, Softwood cuttings.