The USDA Zone info is a great tool for gardeners to help us estimate 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 Havre it's possible to estimate when you can plant bower vine.

Planting Calendar for Bower Vine

Frost tolerance for bower vine:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's probably not a good idea to plant bower vine until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant bower vine in Havre 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. Any later than that and your bower vine may not have a chance to grow to maturity. You can get started a little bit earlier by starting your bower vine indoors.

Last Frost Date

In Havre the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -30°F.

Remember that USDA zone info for Havre may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Havre you get surprised by a frost after May 15 so make sure that you are ready to cover your bower vine in the event of a late frost.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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