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

The USDA zone info for Oak Brook should be reffered to in order to estimate when it's the best time to plant blue throatwort.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You really shouldn't plant blue throatwort until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant blue throatwort in Oak Brook 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 blue throatwort and expect a good harvest is probably August. If you wait any later than that and your blue throatwort may not have a chance to fully mature. You can get started a few weeks earlier by starting your blue throatwort indoors.

Last Frost Date

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

Always keep in mind that USDA zone info for Oak Brook is not always accurate and the actual date of last frost changes from year to year. Half of the time in Oak Brook last frost occurs after April 15 so just be sure to be ready to cover your blue throatwort in the event of a surprise late frost.

USDA Zone Info for Oak Brook

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 Oak Brook

You may be interested in your other planting guides for Oak Brook.