Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Planting
Canna lilies will grow in a wide range of soil types and full sun to light shade. All Canna lilies perform their best in well-drained but moist soil. They spread as they grow and one plant can form a quite large patch over time. If your soil is dense or compacted, I would suggest digging the planting hole at least two wide. Then incorporate organic matter/soil amendment at a 25-50% ratio with the native soil removed from the planting hole. A good organic matter would be mushroom compost, composted cow manure, or your own homemade compost. If your soil is looser, and crumbles well in your hand when dry, you don't need to incorporate as much organic matter. In sandy, quick-draining soil, one might need to add peat moss to hold in some extra moisture.

Canna lilies can also be planted in pots that can be submerged in the garden pond. Here's a link to an article that provides some helpful tips and instructions for planting aquatic plants:

http://www.gardenality.com/Articles/325/How-To-Info/Planting/How-To-Plant-Aquatic-Pond-Plants/How-to-Plant-Aquatic-Plants.html

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Pruning
To prolong the blooming period you can remove dead flowers on canna lilies. Use sharp scissors or pruners to cut the flower stem down to an inch or so above the next node on the stem. This will prompt the flower stem to bloom again. When a flower stem has no buds left on it it can be cut to the ground if desired. After foliage has died completely back from frost you can cut it back to 4 inches above the ground. In cooler climates you can mulch for winter protection.

In zones north of 7b, rhizomes will need to be removed from the soil and stored for winter. Right after the plant has gone dormant, when the foliage has died back but the before the ground becomes frozen, dig the clumps out of the soil with a shovel. Remove most of the soil from around the rhizomes/ bulbs with your fingers. Cut off the dead foliage of each rhizome and then place them in a sheltered spot for a few days until they are thoroughly dry. Then wrap each bulb in newspaper and insert in a cardboard box or mesh bag. Space the rhizomes so they do not touch each other. Store the box in a room such as a garage with temperatures between 40 and 55 degrees Fahrenheit. Inspect the roots regularly and discard those that become rotted.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Feeding
In spring, when plant are starting to emerge from dormancy, I fertilize canna lilies with a low-nitrogen, slow-release, organic plant food. Nitrogen is the first number in fertilizer. High nitrogen fertilizers can cause cannas to grow spindly and weak.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Problems
I've seen no serious disease or insect problems with the Tropicanna varieties of canna lily.