One of the first steps you take when you are getting a good idea 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.

It's possible to figure out when it's a good idea to plant thunbergia by using the USDA zone info for Wausau.

Planting Calendar for Thunbergia

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

Since thunbergia require warm weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant thunbergia in Wausau 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 grow to maturity. Starting your thunbergia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Wausau. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Wausau is just an average the actual date of last frost is different every year. Since half of the time in Wausau there is a last frost after May 15 be ready to cover your thunbergia if you have one of those late frosts.

USDA Zone Info for Wausau

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 Wausau

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