One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's the best time to plant thunbergia is to examine the USDA zone info for Lake Zurich.

Planting Calendar for Thunbergia

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

Thunbergia are not cold tolerant which means that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant thunbergia in Lake Zurich 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. If you wait any later than that and your thunbergia may not have a chance to fully mature. If you are starting your thunbergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Lake Zurich. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Lake Zurich and it will vary from year to year. Since half of the time in Lake Zurich you get a frost after April 15 be ready to protect your thunbergia if you have a surprise late frost.

USDA Zone Info for Lake Zurich

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Lake Zurich

You may be interested in your other planting guides for Lake Zurich.