Sunchoke (Helianthus tuberosus)
Also called Jerusalem artichoke, this plant is related to the sunflower, but perennial. It gives edible tubers and is grown in a similar fashion to potatoes. It is however completely frost hardy and the tubers can remain in the ground over the winter. Many varieties grow small sunflower-like flowers in autumn. The plants can become several meters tall and if you don't watch out they can become weeds.
Some varieties flower in september, but in northern climates they don't have time to set seeds.
