How it changes through the year, and the St Helens garden plants it is most often mistaken for.



From April, red-purple spears with tightly rolled leaves push through the soil and can gain several centimetres in a day.
By July it is two to three metres tall. Stems are hollow and flecked with purple, they kink at every node, and the leaves are broad with a flat base.
Creamy flower sprays open late in the season. Soon afterwards the leaves go yellow and fall.
Dead canes stay upright, brown and brittle. Underground the rhizome is still alive and waiting.
Bindweed twines around whatever it can reach. Dogwood has woody stems and curved leaf veins. Himalayan balsam has pink flowers and favours damp ground, such as the Sankey canal banks. If you are unsure, send a photo.