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

The USDA zone info for Zone 4b should be reviewed to determine 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 well in moderate cold which tells us that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hollyhocks in Zone 4b 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. Any later than that and your hollyhocks may not have a chance to grow to maturity. Starting your hollyhocks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Zone 4b the average date of last frost happens on May 15. You should expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4b is just an average and the actual date of last frost changes from year to year. Since half of the time in Zone 4b it frosts late in the year after May 15 be ready to cover your hollyhocks if you have a surprise late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Zone 4b

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