Starting cannas from seed

Cannas produce copious amounts of seeds that are rounded, dark brown to black in color, and heavy enough to sink in water. Since they resemble shotgun pellets (and could possibly be used as that, considering how hard they are), cannas are sometimes called “Indian shot”.

Canna seeds have a very tough protective coat, presumably to allow them to survive until the next rainy season arrives. To speed up germination, various methods have been proposed. They all involve cutting, clipping, or nicking the seed coat—a method called scarification in horticultural jargon. This allows water to penetrate the seed in order to trigger germination.

After trying various techniques involving nail clippers and emery boards, I’ve settled on the following procedure. I’ve used it successfully in past years to germinate several species of canna. This year I’m trying it on the banana canna (Canna musifolia), one of the tallest species (up to 8 ft.) with possibly the largest leaves of any in this genus. In fact, the leaves strongly resemble bananas, hence the common name.

Just a few of the canna seeds I collected last fall.

Step 1: Nick the seed coat using a Dremel rotary tool. After trying a nail, ice pick, nail clipper, etc., I decided to switch to a Dremel (which we use to file down the dog’s nails) because the seed coat really
is that hard to penetrate.
 

Nicked seed coat—I probably took off a bit too much;
just a tiny nick is needed

Step 2: Put the nicked seeds in a glass of warm water (almost hot) for 48 hours. Replace the water twice a day so it doesn’t go sour.
 

Step 3: Stick the seeds in growing medium and keep it moist
(but not soggy). Keep in a relatively warm place with direct light. The experts call for 70-75°F, but it’s never that warm in our house and it doesn’t seem to matter too much.

Everybody has their own preferred seed growing medium and technique, so by all means, use what works for you. I simply stuck my seeds in small cactus pots filled with a coarse potting mix. I keep it moist by spraying it with a spray bottle. You should see growth in as little as 5 days.

Here are some cannas in our front yard, in the back behind the banana (left), lemon tree (middle) and bamboo (right). Their leaves add a tropical flair, and their flowers are hummingbird magnets.