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

By reviewing the USDA zone info for Downers Grove you should be able to estimate when 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.

Hollyhocks tend to make it in moderate cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant hollyhocks in Downers Grove 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. If you wait any later than that and your hollyhocks may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your hollyhocks indoors.

Last Frost Date

The average date of last frost is April 15 in Downers Grove. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Downers Grove is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Downers Grove there is a last frost after April 15 be ready to protect your hollyhocks in the event of one of those late frosts.

USDA Zone Info for Downers Grove

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 Downers Grove

You may be interested in your other planting guides for Downers Grove.