One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant canna in Rock Springs should be determined by looking at the USDA zone info.

Planting Calendar for Canna

Frost tolerance for canna:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since canna are not cold tolerant it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant canna in Rock Springs is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant canna and expect a good harvest is probably August. If you wait any later than that and your canna may not have a chance to fully mature. If you are starting your canna indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Rock Springs. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Rock Springs and it is different every year. Half of the time in Rock Springs there is a last frost after April 15 so always be ready to cover your canna in the event of one of those late frosts.

USDA Zone Info for Rock Springs

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Rock Springs

You may be interested in your other planting guides for Rock Springs.