Ready-grown potted plants and tubers can be expensive if you are planning on a good display. Unfortunately, Canna is susceptible to ‘Canna Rust’, a disease that affects the leaves, has no effective cure and will eventually cause the death of a plant. The sure-fire way of avoiding the disappointment of losing your prized Cannas is to ‘backup’ your supply and grow from seed. Fortunately, the seed will not carry the virus and growing Cannas in this way is very rewarding.
Cannas are very easy to grow from seed, establish themselves amazingly quickly and may flower in the first year if sown in Autumn or mid-Winter. They will also produce plenty of seeds of their own for next year’s display!
Preparing and planting your Canna seed
You may have noticed that the seed of the Canna Lily is incredibly hard and round. In the past, these dark brown/black seeds have been used in the making of jewelry and are reminiscent of the shot pellets, hence the name ‘Indian shot’.
Because the seeds are so tough, it’s a good idea to file down their outer shells, until the surface becomes slightly lighter as you reach the inner seed. The seeds will then need soaking for about 24 hours in lukewarm before planting within a pot on the surface of moist seed compost. Push each seed into the compost a little and place within a tied plastic bag to conserve moisture
You will then need to place your pot in a dark place at around 20-25C. As soon as germination takes place (usually about 10-20 days), remove your pot from the bag and remove to a bright, frost-free position and maintain a temperature of 20-25C.
Transplant seedlings when large enough to handle into 7.5cm (3in) pots. Harden off and plant out when all risk of frost has passed and space 30cm (12in) apart in full sun.
- Sow seeds during October or February
- File Canna seed’s hard shell
- Soak for 24 hours in lukewarm water
- Sow seeds in pot or tray – just pushing them into compost a little
- Place in plastic bag
- Exclude all light – temp. 20-25C and check daily
- Move to bright position once seedlings appear
- Plant Cannas out when risk of frost has passed