Canna lilies are prized for their vibrant, torch-like flowers and lush, broad foliage. While these plants are most commonly propagated from underground rhizomes, they also produce seeds that can be used to grow new plants. Understanding the appearance and structure of these seeds is the first step for anyone interested in collecting and propagating them. This guide details the physical characteristics of Canna lily seeds and how they develop on the plant.
Physical Characteristics of Canna Seeds
Canna lily seeds are notable for their deep coloration and extreme density, which is why they have historically been known by the common name “Indian shot.” The seeds are typically deep black or a very dark brown when fully mature. Their shape is generally spherical or round, though some can be slightly ovoid or oblong.
The most distinguishing feature of the Canna seed is its exceptionally hard, smooth, shell-like exterior, known botanically as the testa or seed coat. This tough outer layer is impermeable to water, which prevents immediate germination and ensures the seed’s long-term survival. This dense, black shell must be physically compromised for the seed to sprout.
Where Canna Seeds Develop
Canna seeds form inside protective structures called seed pods, which appear after the plant’s showy flowers have faded and pollination has occurred. These pods develop along the flowering stalk and are initially a round, green color. The surface of the capsule is often bumpy or spiky, giving the exterior a rough texture.
Each of these capsules typically contains two to three seeds, though some varieties may hold up to six seeds per pod. The seeds are ready for collection once the pod has fully matured and begins to dry out, turning from green to a brittle brown. The pod may shrivel and start to open, revealing the hard, dark seeds inside.
Preparing Canna Seeds for Growth
The extreme hardness of the Canna seed coat must be addressed before planting to allow moisture to reach the embryo inside and initiate germination. This process, known as scarification, involves physically abrading the outer shell. Gardeners commonly use a metal file, sandpaper, or a sharp knife to gently scratch or nick the seed coat until a small area of the lighter-colored inner material is visible.
After scarification, the seeds must be soaked in warm water for 24 to 48 hours to fully hydrate the embryo. Water absorption causes the seed to swell, signaling that the process has successfully broken the seed’s dormancy. Following soaking, the seeds should be planted about a half-inch deep in a moist, well-draining potting medium. Providing gentle bottom heat, ideally around 70 to 75 degrees Fahrenheit, will accelerate germination.