Plants can rapidly colonize a site by vegetative reproduction from creeping roots. Dalmation and yellow toadflax can hybridize. Seeds produced early in a season have a longer dormant period than seed produced later. Under field conditions, seed may remain viable for up to 10 years. Most seedlings emerge from within 5 mm of the soil surface.
Germination is highest on open sites with compacted soils and little vegetation.
Intense competition with other plants appears to lower or prevent seed production. Seeds can float on water for extended periods and may remain viable for 8 years or more under field conditions. Most seeds are dormant at maturity. A cool, moist period breaks dormancy, and germination of these seeds does not require light. However, evidence suggests that light stimulates germination of seeds that have not had a cool, moist period.