The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's a good idea to plant hollyhocks is to examine the USDA zone info for Cambridge.

Planting Calendar for Hollyhocks

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

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

The earliest that you can plant hollyhocks in Cambridge is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant hollyhocks and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to fully mature. You can get started a few weeks earlier by starting your hollyhocks indoors.

Last Frost Date

In Cambridge the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Cambridge and it will vary from year to year. Half of the time in Cambridge last frost occurs after May 15 so be sure to be ready to cover your hollyhocks if you have a surprise late frost.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

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

Plants to Grow in Cambridge

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