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.

You should be able to figure out when it's possible to plant scarlet pimpernels by using the USDA zone info for Bozeman.

Planting Calendar for Scarlet Pimpernels

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

Since scarlet pimpernels are barely cold tolerant you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant scarlet pimpernels in Bozeman 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 scarlet pimpernels and expect a good harvest is probably August. If you wait any later than that and your scarlet pimpernels may not have a chance to grow to maturity. If you are starting your scarlet pimpernels indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Bozeman the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Bozeman is an average the actual date of last frost is different every year. Half of the time in Bozeman last frost occurs after May 15 so make sure that you are prepared to cover your scarlet pimpernels in the event of one of those late frosts.

USDA Zone Info for Bozeman

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 Bozeman

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