he easiest way to propagate ironweed is by dividing the root system of a mature plant in early spring, separating it into smaller sections with roots and shoots, and replanting them in new locations; you can also try propagating ironweed from seed, but this requires cold stratification (keeping the seeds in the refrigerator for a period of time) to improve germination rates. 

Key points about propagating ironweed:

Division: The most common method, done in early spring when the plant is dormant; carefully dig up the root ball, separate it into smaller sections, and replant each division. 

Seed propagation:

Direct sowing: Plant seeds outdoors in the fall, lightly covering them with soil, as they benefit from cold stratification over winter. 

Indoor starting: Start seeds indoors several months before the last frost, but first, stratify them by placing them in a moist paper towel and refrigerating for a few months. 

Cuttings: Although less common, you can also try taking stem cuttings from new growth and rooting them in a moist potting mix with good drainage. 

Important considerations:

When to divide: Early spring is the best time to divide ironweed plants. 

Seed stratification: Ironweed seeds need cold stratification to germinate well, so either sow them outdoors in fall or refrigerate them before planting indoors. 

Planting location: Choose a sunny spot with well-drained soil for your ironweed plants.