Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Island Lake you can estimate when it's a good idea to plant thunbergia by looking at the USDA zone info.

Planting Calendar for Thunbergia

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

It's probably a bad idea to plant thunbergia until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant thunbergia in Island Lake 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. Starting your thunbergia indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Island Lake the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Just be sure to remember that USDA zone info for Island Lake is an average and the actual date of last frost is different every year. Half of the time in Island Lake it frosts late in the year after April 15 so be sure to be ready to cover your thunbergia in the event of one of those late frosts.

USDA Zone Info for Island Lake

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 Island Lake

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