The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant columbine in Billings can be figured out by looking at 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.

Columbine can survive in a little bit of cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant columbine in Billings is March. However, you really should wait until April 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 grow to maturity. If you are starting your columbine 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 May 15 in Billings. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Billings and it is different every year. Since half of the time in Billings last frost occurs after May 15 be ready to cover your columbine in the event of a surprise late frost.

USDA Zone Info for Billings

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 Billings

You may be interested in your other planting guides for Billings.