Before planting it is a good idea to find your USDA Zone info to estimate 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.

By using the USDA zone info for Rensselaer you should be able to estimate 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.

Common hollyhock are moderately cold tolerant which means that you can plant them earlier than more sensitive plants.

The earliest that you can plant common hollyhock in Rensselaer 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. 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

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

Since the USDA zone info for Rensselaer is just an average the actual date of last frost is different every year. Since half of the time in Rensselaer you get surprised by a frost after April 15 be ready to cover your common hollyhock if you have one of those late frosts.

USDA Zone Info for Rensselaer

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 Rensselaer

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