One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Bozeman can be used to determine when it's possible to plant thunbergia.

Planting Calendar for Thunbergia

Frost tolerance for thunbergia:	Not tolerant of frost.
When to plant:	After the last frost.

Thunbergia are not cold tolerant which tells us that it's necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Bozeman 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 thunbergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your thunbergia may not have a chance to fully mature. Starting your thunbergia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Bozeman. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that USDA zone info for Bozeman is not always accurate and the actual date of last frost is different every year. Since half of the time in Bozeman you get surprised by a frost after May 15 be ready to cover your thunbergia if you have a late frost.

USDA Zone Info for Bozeman

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 Bozeman

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