One of the best tools that you have as gardeners to help us estimate 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.

A way of figuring out when you can plant columbine is to refer to the USDA zone info for Williston.

Planting Calendar for Columbine

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

Columbine do well in moderate cold which means that you can get them planted earlier than plants that are more sensitive to the cold.

The earliest that you can plant columbine in Williston 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. Starting your columbine indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Williston. In the coldest months of winter you should expect an average low temperature of -30°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Williston and it is different every year. Since half of the time in Williston you get a frost after May 15 be ready to protect your columbine in the event of one of those late frosts.

USDA Zone Info for Williston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Williston

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