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.

By using the USDA zone info for Helena it's possible to estimate when it's the best time to plant scarlet pimpernels.

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 do ok in moderate cold you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant scarlet pimpernels in Helena 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 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 fully mature. You can get started a few weeks earlier by starting your scarlet pimpernels indoors.

Last Frost Date

In Helena the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 10°F.

Keep in mind that USDA zone info for Helena is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Helena there is a last frost after March 15 be ready to cover your scarlet pimpernels in the event of a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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