Mystery Plant in Butterfly Bush: Likely a Grafted Rootstock

A thicker, taller trunk with serrated leaves and queen-anne's-lace-type flower clusters growing within a butterfly bush (Buddleia davidii) is almost certainly the rootstock of a grafted plant.

Why It Happens

• Many buddleias are grafted onto vigorous Buddleia species rootstock.
• If the rootstock sends up shoots, they outgrow the scion.
• You cannot separate them—they share one root system.

What to Do

• Dig carefully to find the graft union (knobby transition near soil line).
• If grafted: remove the rootstock shoots at the base whenever they appear. Don't let them dominate.
• If truly two separate plants (rare): dig in early fall (30+ days before frost), separate, and replant immediately.

Long-Term

Buy own-root (non-grafted) buddleias in the future to avoid this issue.

Snip the intruder, nurture the butterfly bush.