Buddleia (or buddleja) are flowering shrubs that produce colorful flowers in late summer and fall. ... Some cultivated species of buddleia, including Buddleia davidii, are banned in parts of the U.S. because the plants can self-sow and be invasive. Fortunately, many of the newer hybrids do not produce viable seeds.

Does buddleia reseed?

Yes, they do. The wild species Buddleia davidii spreads rapidly, invading riverbanks, reforested areas, and open fields.

Does butterfly bush self seed?

All About Butterfly Bush: Planting Tips

To avoid the problem of self-sowing, try to deadhead consistently all summer not letting the seed to set. Butterfly bushes are considered invasive in some states (Oregon, Washington, and Hawaii), so care should be given to not let them spread into the wild.