The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant hardy hibiscus in Zone 4a can be determined by using the USDA zone info.

Planting Calendar for Hardy Hibiscus

Frost tolerance for hardy hibiscus:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Hardy Hibiscus do well in cold which tells us that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant hardy hibiscus 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 hardy hibiscus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hardy hibiscus may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your hardy hibiscus 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 not always accurate the actual date of last frost will vary from year to year. Since half of the time in Zone 4a there is a last frost after May 15 be ready to protect your hardy hibiscus in the event of one of those late frosts.

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.