The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant columbine in Zone 2b should be estimated by reviewing the USDA zone info.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since columbine do well in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant columbine in Zone 2b 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 columbine and expect a good harvest is probably August. Any later than that and your columbine may not have a chance to really do well. If you are starting your columbine indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Zone 2b the average date of last frost happens on May 15. It might get as low as -45°F during the coldest months of winter.

Since the USDA zone info for Zone 2b is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Zone 2b it frosts late in the year after May 15 so always be ready to cover your columbine in the event of a surprise late frost.

USDA Zone Info for Zone 2b

Here is the info for USDA Zone 2b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	August 15
Lowest Expected Low	-45°F
Highest Expected Low	-40°F

This means that on a really cold year, the coldest it will get is -45°F. On most years you should be prepared to experience lows near -40°F.

Plants to Grow in Zone 2b

You may be interested in your other planting guides for Zone 2b.