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

You can figure out when it's a good idea to plant common hollyhock in San Ramon by reviewing the USDA zone info.

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 do well in a little bit of cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant common hollyhock in San Ramon 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. 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

The average date of last frost is February 15 in San Ramon. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Ramon may not be accurate from year to year the actual date of last frost is different every year. Half of the time in San Ramon last frost occurs after February 15 so be sure to be ready to cover your common hollyhock in the event of a surprise late frost.

USDA Zone Info for San Ramon

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Ramon

You may be interested in your other planting guides for San Ramon.