One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Billings you can determine when to plant lupine by looking at the USDA zone info.

Planting Calendar for Lupine

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

Lupine are one of those plants that can tolerate a little bit of cold weather which means that you can start planting them earlier than other plants that might not handle the cold.

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

Last Frost Date

In Billings the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Billings is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Billings it frosts late in the year after May 15 so make sure that you are ready to cover your lupine in the event of a 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.