One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of determining when you can plant hollyhocks is to use the USDA zone info for Colusa.

Planting Calendar for Hollyhocks

Frost tolerance for hollyhocks:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Hollyhocks are moderately cold tolerant which means that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant hollyhocks in Colusa 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 hollyhocks and expect a good harvest is probably October. Any later than that and your hollyhocks may not have a chance to really do well. If you are starting your hollyhocks indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Colusa. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Colusa and it changes from year to year. Half of the time in Colusa there is a last frost after February 15 so make sure that you are ready to protect your hollyhocks if you have a surprise late frost.

USDA Zone Info for Colusa

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 Colusa

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