Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of getting a good idea when it's possible to plant common hollyhock is to consult the USDA zone info for Riverdale.

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 one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant common hollyhock in Riverdale 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. You probably don't want to wait any later than that or else your common hollyhock may not have a chance to really do well. If you are starting your common hollyhock indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Riverdale. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Riverdale is an average the actual date of last frost is different every year. Half of the time in Riverdale last frost occurs after March 15 so make sure that you are ready to cover your common hollyhock in the event of one of those late frosts.

USDA Zone Info for Riverdale

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Riverdale

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