Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 Hillsdale should be reviewed to figure out when 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.

You can plant common hollyhock 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 common hollyhock in Hillsdale 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 fully mature. Starting your common hollyhock indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Hillsdale. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Hillsdale is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsdale last frost occurs after April 15 so make sure that you are ready to cover your common hollyhock in the event of a late frost.

USDA Zone Info for Hillsdale

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 Hillsdale

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