Canna Canna red - Marsh plant, waterside plantDeep red flowers on long, green stems. Red canna gives our pond's edge a colourful twist. The red flowers provide months of beauty! The aquatic plant is a waterside and marsh plant. We can plant the plant along the edge (bank) of our pond. Or we can plant the Canna to 40 cm deep in the pond. Plant the perennial canna in the spring. The flowers bloom in the summer. We prune the plant slightly to shape it with a pruning shear. We remove old leaves and