Unknown plant

Unknown plant

Observation - Unknown plant - UK and Ireland. Description: Possibly a garden escapee! Tall, 3-2 foot rather like nepeta (catmint) but much darker in colour and with no scent. I have no idea what it is.

Possibly a garden escapee! Tall, 3-2 foot rather like nepeta (catmint) but much darker in colour and with no scent. I have no idea what it is.