How-to Guide
How to Grow Cannas
The short answer
Cannas are tropical-looking plants grown from rhizomes. Clemson Extension says to plant them in spring after frost danger passes, 1 to 2 inches deep and 12 to 24 inches apart, in full sun and rich soil with good moisture. In mild-winter areas like South Carolina they can stay in the ground year-round; in cold climates the rhizomes must be lifted each fall.
For storage, the New York Botanical Garden's guidance is to dig the rhizomes after leaves have yellowed, died back, or been killed by a light frost — but before the ground freezes — cut foliage to 2 inches, air-dry about a week at 70 to 80 F, then store around 40 F in a cool, dark place at about 40-50% humidity, packed in peat moss, sand, vermiculite, sawdust, wood shavings, or coir.
When and how deep to plant
- 1Plant after frost — Set rhizomes out in spring once frost danger has passed (Clemson).
- 2Shallow: 1-2 inches — Cannas are planted shallow — 1 to 2 inches deep — and given room, 12 to 24 inches apart.
- 3Feed the site — Rich soil with steady moisture drives the big leaves; cannas are heavy feeders compared with most bulbs.
Sun, soil, and water
Full sun, rich soil, good moisture — cannas are one of the few 'bulbs' that shrug off wet feet in summer. Keep them watered through heat; drought shows up fast as ragged, faded foliage.
Overwintering: dig or mulch?
In mild-winter regions cannas are hardy enough to remain in the ground year-round (Clemson, writing for South Carolina). In cold-winter climates, dig them: wait until leaves yellow, die back, or are killed by a light frost, and get them up before the ground freezes (NYBG).
- 1Cut and lift — Cut back foliage to 2 inches, then carefully dig and rinse the rhizomes (NYBG).
- 2Cure one week — Air-dry about a week in a ventilated space at 70 to 80 F.
- 3Store around 40 F — Cool, dark, and around 40-50% humidity, in non-airtight containers of peat, sand, vermiculite, sawdust, wood shavings, or coir, with rhizomes not touching each other.
- 4Check monthly — Discard shriveled, diseased, or insect-infested rhizomes; lightly moisten the medium if pieces shrivel, air-dry briefly if too damp.
Dividing
Wait until spring to divide stored rhizomes, breaking clumps apart so each division carries at least 3 eyes (NYBG). In-ground clumps in mild climates are divided in spring as well (Clemson).
✔ A storage spot that freezes or an airtight bin are the two classic ways to lose cannas over winter. Basements and frost-free crawl spaces near 40 F are ideal.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Clemson Cooperative Extension HGIC — Summer- and Fall-Flowering Bulbs — Canna planted spring after frost, 1-2 inches deep, 12-24 inches apart, full sun, rich moist soil; can remain in ground year-round in South Carolina; spring division
- New York Botanical Garden, Mertz Library Plant Information — How do I prepare my canna for winter storage? — Dig after leaves yellow/die back/light frost, before ground freezes; cut foliage to 2 inches; air-dry ~1 week at 70-80 F; store ~40 F, dark, 40-50% humidity in peat/sand/vermiculite/sawdust/shavings/coir; check through winter; divide in spring with at least 3 eyes per division