Canna plants are known for their large, bright, beautiful flowers and huge green or multicolored foliage. There are tall varieties with large flowers to use as backdrops in gardens or to line paths and walkways. Smaller varieties are often used in containers or placed among other perennials in the garden. Because they are tropical plants, they are not frost tolerant, but can easily be lifted and overwintered in northern areas or mulched for protection in borderline areas. If you are looking to add a tropical flare to your garden, then these easy and inexpensive flowers are for you.
Check for aphids as the young shoots start to come up, and apply an aphid spray if you see signs. Aphids are not a problem on more mature foliage. Follow the manufacturer's directions on amount and frequency. Place slug and snail traps around young plants, as they like to feed on the foliage as it unravels.
Top-dress the area around the plants with an inch of compost once a month, and gently scratch the surface of the soil to work the compost in a little. Canna plants love lots of compost and will grow larger and fuller the more you use.
Water the plants to keep the soil moist. These plants love lots of water, so soaking them every other day will give you tall flowers and lush foliage. Water every day during hot dry spells in the summer.
Apply a high-phosphorus fertilizer once a month to the soil around the plants. Follow the manufacturer's directions on the amount.
Mulch the flower bed with 2 inches of a bark mulch once the plants have emerged and you can see exactly where they are. For gardening zones 9 and those south, add another inch of mulch when the foliage dies off for the winter, and water once a month.
Lift the rhizome out of the ground with the gardening fork once the first freeze has killed off the rest of the foliage in gardening zones 8 and those north. There will be more rhizomes than when you planted, so be careful not to damage them.
Place the rhizome clumps in plastic flower pots and sprinkle on some water. Keep them in a frost-protected area and don't allow them to completely dry out. Plant them out again after the last threat of frost has passed in the spring. If you want to divide the rhizomes, do so in the spring.