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 Willowbrook can be reviewed to determine when it's a good idea to plant hollyhocks.

Planting Calendar for Hollyhocks

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

You can plant hollyhocks a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant hollyhocks 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 hollyhocks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to fully mature. Starting your hollyhocks indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Willowbrook. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Willowbrook and it is different every year. Since half of the time in Willowbrook you get surprised by a frost after April 15 be ready to cover your hollyhocks 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.