Cannova Bronze Scarlet is one of the easier cannas to grow, thriving in full sun with consistently moist soil and warm temperatures above about 15°C (60°F). This seed-grown hybrid from the Cannova series pairs deep bronze-purple foliage with vivid scarlet flowers on compact plants that typically reach 90 to 120 cm tall. It performs well in garden beds and large containers alike, but getting the best results depends on a few details that trip up first-time canna growers.
What Sets Cannova Bronze Scarlet Apart
The Cannova series was bred for uniformity and early flowering from seed, which makes these plants different from many traditional cannas that are propagated exclusively by dividing rhizomes. Cannova Bronze Scarlet flowers earlier in the season than most older cultivars, often blooming within 10 to 12 weeks of transplanting into warm soil. The bronze foliage is not just a backdrop for the scarlet blooms; it holds ornamental value on its own. New leaves emerge with a rich purple-bronze sheen that darkens as they mature, creating a layered color effect even before the first flower spike appears.
Because the Cannova line was selected for a compact habit, you won’t get the towering 1.8-metre plants that some heritage cannas produce. That shorter, sturdier frame means less staking and less flopping in wind, which is a real advantage in exposed garden spots or on balconies.
Choosing a Planting Site
Full sun is non-negotiable if you want strong foliage color and heavy flowering. In practice, that means at least six hours of direct sunlight per day, and more is better. Plants grown in partial shade tend to stretch, lose the intensity of the bronze leaf pigment, and produce fewer flower spikes. In very hot climates with intense afternoon sun, a touch of filtered light in the hottest part of the day is fine, but default to as much sun as you can give them.
Soil should be rich, moisture-retentive, and well-drained. That sounds like a contradiction, but what cannas want is soil that holds water without becoming waterlogged. Heavy clay that puddles after rain will rot the rhizomes. Sandy soil that dries out in hours will stunt growth. The sweet spot is loamy garden soil amended with compost or well-rotted manure. If your native soil is heavy clay, raise the bed or plant into a mound to improve drainage. If it’s very sandy, work in plenty of organic matter to boost water retention.
Soil pH is not particularly fussy for cannas. They perform well across a range from mildly acidic to neutral, roughly 6.0 to 7.0. Testing isn’t essential unless your garden has known pH extremes.
When and How to Plant
Timing matters more than technique. Cannas are tropical plants that resent cold soil. Planting rhizomes or transplants into ground cooler than about 15°C (60°F) leads to slow, weak establishment and invites rot. In most temperate climates, that means waiting until late spring, at least two weeks after the last expected frost. If you’re eager to get a head start, pot up the rhizomes indoors four to six weeks before your outdoor planting date, keeping them in a warm spot around 21 to 24°C. By the time the garden warms up, you’ll have growing plants ready to transplant.
Research on canna seed germination confirms that the genus performs across a wide temperature window, roughly 10 to 40°C, but the optimal range sits between about 14 and 34°C.1Seed Science and Technology. Temperature effect on seed germination in Canna indica L. (Cannaceae) Rhizome sprouting follows a similar pattern: warm soil speeds everything up, while cold soil stalls growth or worse.
Plant rhizomes about 10 to 15 cm deep, with the eyes (growing points) facing upward. Space Cannova Bronze Scarlet plants roughly 40 to 50 cm apart. Their compact habit means they fill in nicely at that spacing without crowding, while still creating the massed tropical look that cannas do best.
Watering
Cannas are thirsty plants. Their large leaves lose moisture quickly through transpiration, and the fleshy rhizomes store water but still need consistent replenishment. During active growth in summer, plan on deep watering at least two to three times per week in garden beds, and daily in containers during hot weather. The goal is to keep the root zone evenly moist without letting water stand around the rhizome for extended periods.
Underwatering shows up quickly as browning leaf edges and stunted flower spikes. Overwatering in poorly drained soil shows up as yellowing lower leaves and, eventually, soft, mushy rhizomes. If you’re growing Cannova Bronze Scarlet in a container, make sure the pot has drainage holes and use a moisture-retentive but free-draining potting mix. A saucer underneath is fine as long as you empty standing water after an hour or so.
One approach that works well in hot climates is to position cannas at the edge of a rain garden or in a low spot where moisture naturally collects. Cannas tolerate boggy conditions better than most ornamentals, and some growers even grow them in shallow standing water as marginal pond plants. Just avoid deep submersion of the crown during early establishment.
Feeding for Best Performance
Cannas are heavy feeders. The combination of large foliage, rapid growth, and continuous flowering demands more nutrition than most garden perennials. Work a slow-release balanced fertilizer into the soil at planting time, and supplement with a liquid feed every two to three weeks through the growing season. A fertilizer with a slightly higher middle number (phosphorus) encourages flowering, but balanced formulations work well too.
Bronze-leafed cultivars like Cannova Bronze Scarlet benefit from adequate potassium, which supports the anthocyanin pigments responsible for the dark leaf color. If foliage starts to look washed out or greenish despite full sun, a potassium-rich feed can help restore intensity. Organic options like compost tea, fish emulsion, or seaweed extract all work and have the side benefit of improving soil biology over time.
Stop fertilizing about six weeks before your expected first frost if you plan to overwinter the rhizomes. This lets the plant wind down naturally rather than pushing soft new growth into cold weather.
Temperature and Cold Hardiness
Cannova Bronze Scarlet is reliably perennial in USDA zones 8 through 11, where winter soil temperatures stay above freezing. In zones 7 and colder, you either dig and store the rhizomes or treat the plant as an annual. The genus has very limited cold tolerance: research evaluating freezing hardiness in ornamental geophytes found that canna cultivars were freezing-sensitive, with lethal damage occurring at temperatures only slightly below freezing, and their cold tolerance did not improve with autumn acclimatization the way some hardier bulbs did.2Acta Horticulturae. EVALUATION OF FREEZING HARDINESS OF ORNAMENTAL GEOPHYTES
In practice, a hard frost will kill the foliage outright, and sustained soil temperatures below freezing will destroy the rhizome. Even in zone 8, a thick mulch layer (10 to 15 cm of straw, shredded leaves, or bark) over the dormant rhizomes provides helpful insurance against unexpected cold snaps.
Overwintering Rhizomes in Cold Climates
If you garden in a region with freezing winters, lifting and storing canna rhizomes is straightforward. After the first frost blackens the foliage, cut the stems back to about 10 cm above the rhizome. Carefully dig the clump, shake off loose soil, and let the rhizomes air-dry in a sheltered spot for a day or two. Then pack them in slightly damp peat moss, vermiculite, or shredded newspaper inside a cardboard box or paper bag. Storage temperature should be cool but above freezing.
Research on short-term storage of canna rhizomes found that exposure to temperatures from 0 to 10°C for up to eight days did not kill the rhizomes, but storage at 0°C for eight days resulted in plants that were shorter and produced fewer shoots compared to unstored controls.3Acta Horticulturae. INFLUENCE OF SHORT-TERM STORAGE TEMPERATURE AND DURATION OF CANNA RHIZOMES ON SUBSEQUENT GREENHOUSE FORCING That finding suggests a sweet spot around 5 to 10°C for winter storage, which conveniently matches an unheated garage, cool basement, or root cellar in most homes. Check the rhizomes periodically over winter, misting lightly if the packing medium has dried out completely, and discard any that have turned soft or developed mold.
In spring, inspect the stored rhizomes for firm, healthy eyes. Divide any large clumps by cutting between the eyes with a clean, sharp knife, letting the cut surfaces dry for a day before planting. Each division should have at least one strong eye and a section of healthy rhizome.
Pests to Watch For
Cannas have relatively few serious insect pests, but a handful show up regularly. Canna leaf rollers, the caterpillars of a small moth, are the most notorious. They roll themselves inside the leaves and chew from the inside out, leaving ragged, brown-edged foliage. If you see leaves that are stuck together or rolled tightly, unroll them and remove the caterpillar by hand. For heavier infestations, Bacillus thuringiensis (Bt) sprays target caterpillars without harming beneficial insects.
Japanese beetles, slugs, and snails also feed on canna leaves. Japanese beetles skeletonize the foliage, leaving lace-like holes. Hand-picking in the morning when beetles are sluggish is effective for small populations. Slugs and snails leave irregular holes and slime trails; iron phosphate bait is an effective and pet-safe control.
Aphids occasionally colonize flower buds and young growth. A strong spray of water usually dislodges them, and they rarely cause lasting damage on vigorous cannas.
Virus Diseases in Cannas
The most important disease concern for cannas isn’t a fungus or bacterium but a group of viruses. Canna yellow mottle virus (CaYMV) has been identified in canna populations in multiple regions, and no insect vector has been confirmed for it, meaning it spreads primarily through infected planting material.4Plant Health Progress. Canna yellow mottle virus Detected in Canna in Florida That makes buying clean, virus-tested stock your best defense.
Symptoms of viral infection in cannas include severe mosaic patterns, streaking, and necrosis on leaves. Research examining five different plant viruses in cannas found that some viruses suppressed the red and bronze coloration in foliage, which is particularly relevant for a cultivar like Cannova Bronze Scarlet whose ornamental value depends on that pigment. Two viruses, CaYMV and canna yellow streak virus, frequently appeared together in the same plant, suggesting a viral complex that makes diagnosis harder.5Plant Pathology. Production of discernible disease phenotypes in Canna by five plant viruses belonging to the genera Potyvirus, Cucumovirus and Badnavirus
There is no cure for virus-infected cannas. Infected plants should be removed and destroyed rather than composted, because the virus persists in rhizome tissue. Do not divide and share rhizomes from plants showing mosaic or streak symptoms, even if the rest of the plant looks healthy. When buying new stock, purchase from reputable nurseries that certify virus-free production.
Other Disease Issues
Aside from viruses, cannas can suffer from fungal rust, which appears as orange-brown pustules on the undersides of leaves. Rust is more common in humid conditions with poor air circulation. Thinning crowded clumps, watering at soil level rather than overhead, and removing infected leaves early usually keeps it in check. Fungicide sprays are available but rarely necessary in well-managed gardens.
Bacterial bud rot can strike in overly wet conditions, particularly when water sits in the leaf funnels during cool weather. It causes flower buds to turn brown and mushy before they open. Good drainage, proper spacing, and watering at the base rather than from overhead are the main preventive measures.
Deadheading and Grooming
Cannova Bronze Scarlet flowers on terminal spikes, with individual blooms opening from the bottom of the spike upward over several weeks. As lower flowers fade, they detract from the display. Snapping off spent blooms keeps the spike looking fresh. Once an entire spike has finished flowering, cut it back to the nearest side shoot or down to the foliage. This redirects the plant’s energy into producing new flower spikes rather than setting seed.
Yellowing or tattered lower leaves are normal as the season progresses. Peel or cut them off close to the stem to keep the plant looking clean. This also improves air circulation around the base of the plant, reducing humidity that can encourage fungal problems.
Growing in Containers
Cannova Bronze Scarlet is one of the better cannas for container culture, thanks to its compact size. Use a pot at least 30 cm in diameter and depth, ideally larger. A single rhizome fills a 30-cm pot nicely; for a bigger container, plant two or three for a fuller look. Use a good-quality potting mix and consider adding a scoop of compost for extra fertility.
Containers dry out much faster than garden beds, so daily watering in summer is often necessary. Self-watering pots or drip irrigation on a timer take the guesswork out of this. Feed container-grown cannas more frequently than in-ground plants, roughly every two weeks with a dilute liquid fertilizer, since frequent watering leaches nutrients from the potting mix.
Containers also make overwintering simpler in borderline climates. You can move the whole pot into an unheated garage or shed when frost threatens, rather than digging rhizomes. Let the foliage die back naturally, then stop watering and store the pot in a cool, dark spot until spring.
Companion Planting and Design Ideas
The bronze foliage of Cannova Bronze Scarlet works as a dark anchor in mixed plantings. It pairs well with lime-green foliage plants like sweet potato vine or coleus, creating strong contrast. Silver-leafed companions such as dusty miller or artemisia also complement the dark leaves without competing for visual attention. For a hotter color scheme, plant it alongside orange or yellow zinnias, marigolds, or rudbeckia.
In large containers, try combining Cannova Bronze Scarlet as the “thriller” centerpiece with trailing plants like purple heart or creeping jenny cascading over the edges. The dark leaves and scarlet flowers provide a bold focal point that smaller plants can play off of.
Because cannas are so visually dominant, they work best in groupings of three or more rather than scattered as singles through a border. Mass planting amplifies the tropical effect and makes the foliage color read from a distance. Even a cluster of three plants at the back of a sunny border can anchor the entire bed.
Propagation
The most practical way to increase your Cannova Bronze Scarlet stock is rhizome division, done in spring when you bring stored rhizomes out of dormancy or when you dig established clumps in warmer zones. Each division needs at least one healthy growing eye and a fist-sized portion of rhizome to establish quickly.
Growing Cannova cannas from seed is technically possible, since the series was bred as a seed-propagated line, but it requires patience. Canna seeds have an extremely hard seed coat that must be nicked with a file or soaked in warm water for 24 to 48 hours before sowing. Even with scarification, germination can be erratic and slow. Seedlings need warm, bright conditions and several months of growth before they reach transplant size. For most home gardeners, buying started plants or rhizomes from a nursery is far simpler than starting from seed.
When dividing rhizomes, use a clean knife to reduce the chance of spreading any viral infections between divisions. If you suspect a parent plant was virus-infected based on mosaic symptoms, do not propagate from it at all. It’s better to start fresh with certified clean material than to perpetuate a virus through your collection.
Seasonal Timeline for Temperate Growers
Keeping cannas on schedule makes the difference between a plant that blooms in midsummer and one that barely gets going before frost. Here is a rough calendar for gardeners in zones 5 through 7, where the growing season is limited:
- Late winter: Inspect stored rhizomes, discard any that are soft or moldy, and pot up healthy ones indoors in a warm room to get a head start.
- Mid to late spring: Once nighttime temperatures reliably stay above 10°C and soil has warmed, transplant potted-up cannas into the garden or move containers outdoors. Harden them off over a week if they’ve been growing under artificial light.
- Summer: Water deeply and feed regularly. Deadhead spent flower spikes to encourage continuous blooming. Watch for canna leaf rollers and hand-pick as needed.
- Early autumn: Stop fertilizing. Enjoy the last flush of blooms.
- After first frost: Cut back blackened foliage, dig rhizomes, dry briefly, and store at 5 to 10°C in damp packing material.
In zones 8 and warmer, the timeline compresses. You can leave rhizomes in the ground year-round with a protective mulch, and plants emerge on their own in spring without any indoor start. The main task in those zones is dividing clumps every two to three years to prevent overcrowding, which reduces flowering over time.