The Canna lily, which is also known as water canna or aquatic canna, belongs to the genus Canna. This genus consists of a variety of subtropical and tropical species that produce beautiful flowers and equally stunning leaves that will give any pond or water garden a little something extra.
Canna erebus is a cultivar of Canna glauca, a species known for large tropical plants that produce summer flowers of all different shades. The flowers are showy, yet elegant (somewhat mimicking a gladiolus), and in this cultivar turn a salmon pink. The bluish-green paddle-shaped leaves add a beauty that stays all year round depending on your hardiness zone, long after the flowers are gone. This plant draws in a variety of colorful pollinators such as butterflies and hummingbirds that will bring further diversity to your pond.
Cannas aren’t just popular as garden flowers; the seeds of canna are beautiful and can be worked into different jewelry pieces by using them as beads. Or maybe jewelry isn’t your thing. Young canna seeds can also be used to make tortillas or feed for animals. These uses for water canna seeds are more common in the areas of South and Central America where cannas are natively from.
Facts, Benefits & Uses of Water Canna
Canna erebus offers an impressive résumé for the environment with its ability to attract pollinators and remove harmful elements from wastewater. In terms of pollinators, this plant attracts butterflies and hummingbirds, making your pond a valuable safe haven to these critically important creatures. There are also studies on how canna lilies are successful at removing ammonia nitrogen from water without putting any extra unnecessary strains on the environment. In fact, cannas are able to remove as much as 98% of the ammonia nitrogen found in test wetland ecosystems.
You may find this extra tidbit interesting if you find yourself desperate for a snack: if you know, or are willing to learn, how to properly prepare the rhizomes of Canna erebus, they are edible!
Water Canna Growth, Hardiness & Climate
This fast-growing perennial has stunning bluish-green leaves with salmon pink flowers that bloom in late summer from July to around September, with their full height being anywhere from three to six feet and a one to three foot spread. The blooms can last anywhere from a couple of days to several weeks depending on the climate that they are growing in, though it should be noted that water cannas prefer moist, warm climates as they hail from South America.
A hardiness zone of seven and above is good, but they usually begin to thrive once you get more into zones eight through ten. Canna erebus prefers areas of full sun to partial shade with moist, rich, well-draining soils like those found in their native subtropical to tropical range.
How to Plant Water Canna In Ponds
When planting water canna in a pond, if planting an already mature plant be sure that crown of the plant (where the roots attach to the stem) is under no more than 8 inches of water and soil. For best results, the roots should be placed in at least 2 to 4 inches of soil to help hold the plant in place, with another 4 to 6 inches of water above that per to the aforementioned 8 inch rule. If planting from bulbs, these would do best if planted in just enough damp, rich soil to cover the top of the bulb. Once established, you can transplant it to the shallow margins of your pond, if desired.
In order to prevent the rhizomes from spreading and keep your pond from having more water cannas than planned, consider using an aquatic planting basket in order to keep these beautiful flowers where they were intended. These baskets will still allow the plant’s roots to obtain the oxygen and nutrients they need, but will help deter them from spreading outside of the basket. If you are not putting them in a pond, the plant needs to stay in rich, moist soils and watered often.
How to Care For Water Canna
The water canna needs to be kept damp if you choose to not plant in a pond. Keep the soil damp, but properly drained to avoid a visit from pests or blight that could be harmful to the plant’s health. Keep dropped flowers and leaves cleaned up to allow your pond to stay in pristine condition, this can be done while deadheading during the blooming season to cut down on potential cleanup and keep the blooms looking impeccable.
As long as you ensure that your canna is planted at hardiness zone 7 or above, is free of blight and beetles, and getting full sunlight to partial shade, your water canna should be happy.
How to Winter Water Canna
Due to Canna erebus being more of a tropical plant, it will not survive in locations that experience frost and winter. If you live in a warmer area with a potential for frost, a thick 6 inch layer of mulch can be placed around the plant, whereas in colder zones further north, you will need to transfer the plant indoors or take it to a greenhouse area (after cutting down growth to about the six-inch mark) to keep it away from harmful ice and snow. For best results, store the bulbs in a location that is 50 to 60° F (10 to 15.5° C). It is important to note that moving plants can cause them stress, and some losses may be inevitable; for this reason, it’s often easiest and safest to simply move the bulbs rather than the entire plant.
Is Water Canna Toxic, Poisonous or Invasive?
Plants with rhizomes can be aggressive, as rhizomes are specially modified rooting structures that double as reproductive structures – each rhizome has the potential to give rise to multiple new plants. Canna erebus has the ability to spread, but can be easily controlled by being planted in containers or baskets with holes in the bottom as their rhizomes aren’t overly strong or aggressive. This plant is not known to be an invasive species and would be better classified as a non-native species, though we always encourage you to utilize plants that are native to your area.
All members of the Canna genus are considered non-toxic, and therefore it can be reasonably deduced that water canna and its relatives are safe for fish.
Is Water Canna Edible? Will Fish Eat it?
It is extremely unlikely that the fish in your pond will decide to feast on your water canna plants. However, if they choose to nibble on the tender roots, don’t worry! The canna family is known to be non-toxic, and in fact have historically been used as a human food source (the seeds can be mashed into a flour-like substance, while the rhizomes can be cooked and eaten if done properly).
Where to Buy Water Canna & Seeds? (UK & US)
In the US, water canna can be bought from many local plant nurseries as well as online. In the UK, however, your best bet would be to purchase it from an online nursery. Some nurseries may be able to special order it in if you inquire about this.
