One of the best tools that you have as gardeners to help us estimate 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.

It's a good idea to figure out when it's the best time to plant purple bell vines by looking at the USDA zone info for Billings.

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 do ok in moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant purple bell vines 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 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 really do well. If you are starting your purple bell vines indoors then you might be able to get away with starting them a little bit 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.

Remember that USDA zone info for Billings may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Billings it frosts late in the year after May 15 be ready to protect your purple bell vines 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.