The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant purple bell vines in Helena can be estimated by reviewing the USDA zone info.

Planting Calendar for Purple Bell Vines

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

Purple Bell Vines are barely cold tolerant which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant purple bell vines 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 purple bell vines and expect a good harvest is probably August. If you wait any later than that and your purple bell vines may not have a chance to fully mature. You can get started a few weeks earlier by starting your purple bell vines indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Keep in mind that USDA zone info for Helena may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Helena it frosts late in the year after March 15 be ready to cover your purple bell vines in the event of a surprise 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.