The USDA Zone info is a great tool for gardeners to help us determine 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 best time to plant bower vine in Helena should be determined by reviewing the USDA zone info.

Planting Calendar for Bower Vine

Frost tolerance for bower vine:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since bower vine require warm weather it is important to wait until after the last frost before you can plant them.

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

The last month that you can plant bower vine and expect a good harvest is probably August. If you wait any later than that and your bower vine may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your bower vine indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Helena. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Helena it frosts late in the year after May 15 so make sure that you are ready to cover your bower vine in the event of a surprise late frost.

USDA Zone Info for Helena

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 Helena

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