One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

One way of getting a good idea when it's a good idea to plant thunbergia is to look at the USDA zone info for Napoleon.

Planting Calendar for Thunbergia

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

Thunbergia do not do well in cold weather which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant thunbergia in Napoleon 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. Any later than that and your thunbergia may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your thunbergia indoors.

Last Frost Date

The average date of last frost is April 15 in Napoleon. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Napoleon is an average the actual date of last frost changes from year to year. Since half of the time in Napoleon you get surprised by a frost after April 15 be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Napoleon

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 Napoleon

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