Certainly one of the largest hardy herbaceous plants which can be grown in the U.K. producing large, puckered and lobed leaves on spiky stems above huge statuesque spikes of tiny reddish-green flowers. Near water this plant can grow enormous.
For best results, sow immediately onto a good soil-based compost. Cover the seeds with fine grit or compost to approximately their own depth. They can be sown at any time, and germination can sometimes be quicker if kept at 15 to 20 degrees C. We sow most seeds in an unheated greenhouse and wait for natural germination, as many seeds have built-in dormancy mechanisms, often waiting for natural spring germination, hence giving them a full season of growth. These gunnera seeds can be very, very slow indeed in germinating, usually taking from 6 to 18 months to appear above the compost. Please be very patient indeed.