One of the first steps you take when you are determining your gardening schedule is find your 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.

The USDA zone info for Polson can be read to estimate when it's a good idea to plant thunbergia.

Planting Calendar for Thunbergia

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

It's not a good idea to plant thunbergia until after the last frost has passed because they require warm weather.

The earliest that you can plant thunbergia in Polson 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 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. You can get started a few weeks earlier by starting your thunbergia indoors.

Last Frost Date

In Polson the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Polson and it will vary from year to year. Since half of the time in Polson it frosts late in the year after April 15 be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Polson

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Polson

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