The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant thunbergia in Glen Ellyn should be figured out by looking at the USDA zone info.

Planting Calendar for Thunbergia

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

Thunbergia require warm weather which means that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant thunbergia in Glen Ellyn 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 fully mature. You can get started a little bit earlier by starting your thunbergia indoors.

Last Frost Date

In Glen Ellyn the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Glen Ellyn is just an average the actual date of last frost changes from year to year. Half of the time in Glen Ellyn it frosts late in the year after April 15 so be sure to be ready to cover your thunbergia in the event of a surprise late frost.

USDA Zone Info for Glen Ellyn

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 Glen Ellyn

You may be interested in your other planting guides for Glen Ellyn.