How to Grow Canna Bulbs
1-When to Plant your Canna Bulbs:
In the North, start the Canna bulbs (rhizomes) indoors about six weeks before your last frost in pots of good, rich potting soil. The pots should be in a warm, sunny area and kept well-watered. The Canna bulbs may also be planted directly in the ground after the last frost when the ground is warm, but they may be slow to start growth and late to bloom. In frost-free areas, the bulbs can be planted at any time. While a frost may kill all the foliage in some areas above zone 8, the Canna bulbs will survive underground if protected with mulch.
2- Where to Plant your Canna Bulbs:
Cannas will grow almost anywhere, as a perennial in the South and a summer flowering plant whose bulbs can be easily lifted and stored in the North. Choose a spot in your garden that receives full sunlight. Although considered tropical plants, cannas actually do well in more temperate climates that receive at least six hours of sunlight per day in the summertime. The Canna bulbs should be planted in a location where the soil drains well. Unlike most bulbs, cannas can thrive in moist soils but will not tolerate standing in water puddles.
3- How to Plant your Canna Bulbs:
For outdoor planting, dig holes that are 4 to 6 inches deep, and 2 feet apart for tall varieties and 1 foot for the others. Then dig in a little peat moss and perlite. For planting in pots, fill a large pot to within 6 inches of the top with a well-draining potting mix into which you have added a little peat moss and perlite. Place one bulb into each hole. If your pot is large, you can plant two or three canna bulbs in each pot. Backfill your pot or hole with additional soil until the bulb and roots are well covered. Gently pat down the dirt around the base. Water your new plant well and expect it to begin sending out new leaves and, when the weather is warm, flowers.
4- How to Care for your Canna Bulbs:
In climates that are warm year round, Callas can remain in the ground and given a dose of fertilizer in the spring to start the growing process over again. Frost will kill them during the cooler months, but if you mulch with straw, old leaves or other organic matter in the fall, your cannas should come back with vibrant new foliage and flowers the following spring. In climates where the ground freezes hard in the winter, you may dig up your plants in the fall, after the first frost, let them air dry for a few days and try storing your bulbs in a cool dry place (in a paper bag or a box filled with peat moss). You may get lucky and manage to preserve the bulbs for next spring planting.