One of the best tools that you have as gardeners to help us determine 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.

In Willowbrook you can estimate when it's the best time to plant coreopsis by looking at the USDA zone info.

Planting Calendar for Coreopsis

Frost tolerance for coreopsis:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Coreopsis are moderately cold tolerant which means that you can plant them earlier than other frost tender plants.

The earliest that you can plant coreopsis in Willowbrook is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant coreopsis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your coreopsis may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your coreopsis indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Willowbrook is just an average and the actual date of last frost is different every year. Half of the time in Willowbrook you get a frost after April 15 so just be sure to be ready to protect your coreopsis in the event of a surprise late frost.

USDA Zone Info for Willowbrook

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 Willowbrook

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