One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant calliopsis in Willowbrook should be estimated by reviewing the USDA zone info.

Planting Calendar for Calliopsis

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

Calliopsis are not cold tolerant which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant calliopsis in Willowbrook 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 calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to fully mature. Starting your calliopsis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Willowbrook. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Willowbrook is not always accurate the actual date of last frost changes from year to year. Since half of the time in Willowbrook it frosts late in the year after April 15 be ready to protect your calliopsis in the event of one of those late frosts.

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.