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

By reviewing the USDA zone info for Calistoga you should be able to determine when it's possible 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 get them planted earlier than other plants that might not handle the cold.

The earliest that you can plant common hollyhock in Calistoga is January. However, you really should wait until February 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 October. Any later than that and your common hollyhock may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your common hollyhock indoors.

Last Frost Date

In Calistoga the average date of last frost happens on February 15. You can expect an average low temperature of 20°F in the coldest months of winter.

Remember that USDA zone info for Calistoga is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Calistoga there is a last frost after February 15 be ready to protect your common hollyhock if you have one of those late frosts.

USDA Zone Info for Calistoga

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Calistoga

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