One of the first steps you take when you are estimating 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.

A common way of figuring out when to plant bells of ireland is to examine the USDA zone info for Billings.

Planting Calendar for Bells of Ireland

Frost tolerance for bells of ireland:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since bells of ireland are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant bells of ireland in Billings 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 bells of ireland and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bells of ireland may not have a chance to fully mature. You can get started a little bit earlier by starting your bells of ireland indoors.

Last Frost Date

On average the last frost is on May 15 in Billings. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Billings is not always accurate the actual date of last frost changes from year to year. Half of the time in Billings there is a last frost after May 15 so always be ready to cover your bells of ireland in the event of one of those late frosts.

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.