One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Zone 4b can be reffered to in order to figure out when to plant canna.

Planting Calendar for Canna

Frost tolerance for canna:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You should not plant canna until after all chance of frost has passed because they require warm weather.

The earliest that you can plant canna in Zone 4b is May. However, you really should wait until June 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. 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

The average date of last frost is May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Zone 4b is an average the actual date of last frost will vary from year to year. Half of the time in Zone 4b you get surprised by a frost after May 15 so be sure to be ready to protect your canna if you have one of those late frosts.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.