One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for Vernon Hills can be used to determine when it's a good idea to plant common hollyhock.

Planting Calendar for Common hollyhock

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

Common hollyhock are moderately cold tolerant which means that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant common hollyhock in Vernon Hills 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 common hollyhock and expect a good harvest is probably September. If you wait any later than that and your common hollyhock may not have a chance to really do well. Starting your common hollyhock indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Vernon Hills the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Vernon Hills may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Vernon Hills you get surprised by a frost after April 15 be ready to cover your common hollyhock in the event of a late frost.

USDA Zone Info for Vernon Hills

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 Vernon Hills

You may be interested in your other planting guides for Vernon Hills.