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

The best time to plant hollyhocks in Hillsborough can be determined by checking out the USDA zone info.

Planting Calendar for Hollyhocks

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

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

The earliest that you can plant hollyhocks in Hillsborough 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 hollyhocks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to fully mature. If you are starting your hollyhocks 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 April 15 in Hillsborough. You can expect an average low temperature of 5°F in the coldest months of winter.

Remember that USDA zone info for Hillsborough is not always accurate and the actual date of last frost changes from year to year. Half of the time in Hillsborough you get a frost after April 15 so just be sure to be ready to cover your hollyhocks in the event of a surprise late frost.

USDA Zone Info for Hillsborough

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Hillsborough

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