This grower is sure of this plant identification.
Please note you will have to dig this plant out.
Leycesteria genus. This genus has about 6 deciduous or semi-evergreen shrubs. They form clumps of arching cane-like stems, with leaves that are oval with pointed tips and finely serrated edges, and are usually borne in pairs. The flowers are small and tubular or sometimes pea-shaped.
They are easily grown in any well-drained soil with full sun or partial-shade. They are mostly frost hardy.
Grown for their showy flower clusters. Suitable for coastal conditions.