One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. 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 Zone 4a you will be able to figure out when you can plant hollyhocks.

Planting Calendar for Hollyhocks

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

Hollyhocks do ok in mild cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant hollyhocks in Zone 4a 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 little bit earlier by starting your hollyhocks indoors.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Zone 4a is just an average the actual date of last frost is different every year. Half of the time in Zone 4a 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 Zone 4a

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 Zone 4a

You may be interested in your other planting guides for Zone 4a.