GLBT AMERICA gardening Tropical canna lilies need warm soil to flourish is northern climates

Tropical canna lilies need warm soil to flourish is northern climates

Many longtime gardeners consider canna lilies the workhorse of the flower garden. That’s because they are available in such a wide range of flower colors, sizes and foliage color.

Canna lilies — or just cannas since they are not actually lilies —  are loosely classified as tender bulbs or summer flowering bulbs as opposed to spring flowering bulbs like tulips, hyacinths and daffodils.

Even though they are commonly called bulbs, they are not true bulbs rather they are specialized underground stems called rhizomes.  In cannas rhizomes store food; are a way for the plant to reproduce asexually; and help anchor the plant.  

They are tropical plants so they can’t survive our cold winter temperatures. In tropical regions they are perennial plants, but here in our climate we have to plant rhizomes every year. 

Many gardeners dig their bulbs every fall and store them over winter. It’s a relatively easy way to build up the number of bulbs over time.

Canna rhizomes are easy to overwinter. In the storage container under the straw, the canna bulbs looked in fine condition this spring.

Because they are tropical plants, cannas require warm soil, so we need to wait until the soil is warm enough to plant in the spring, generally around 60 degrees Fahrenheit. We are approaching those conditions now.

If you are unsure of your soil temperature, dig down a few inches and use a soil thermometer to determine how warm the soil is. If you don’t have a soil thermometer, a kitchen thermometer works just as well. By the time we reach Memorial Day however, you can count on the soil temperatures being pretty stable in the 60s and warm enough to plant.

Check the soil temperature at planting depth. Cover the rhizomes with an inch or two of soil.

Cannas are very versatile in the garden. They can be used in a number of ways  to enhance your garden landscape. They can be an integral part of the design especially if you want a lush, tropical look. 

The plants themselves range in size from under 2 feet to some varieties that grow to 6 or 8 feet tall. Most common varieties are about 4 to 5 feet tall at maturity.