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.

You will be able to figure out when it's possible to plant vinca vine by checking out the USDA zone info for Helena.

Planting Calendar for Vinca Vine

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

Vinca Vine can survive in mild cold which tells us that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant vinca vine in Helena is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant vinca vine and expect a good harvest is probably September. Any later than that and your vinca vine may not have a chance to fully mature. Starting your vinca vine indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Helena the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

Keep in mind that USDA zone info for Helena is 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 you get surprised by a frost after March 15 be ready to protect your vinca vine if you have 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.