Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Zone 3b it's a good idea to determine when it's the best time to plant hardy hibiscus.

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 plant them a quite a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant hardy hibiscus in Zone 3b 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. If you wait any later than that and your hardy hibiscus may not have a chance to fully mature. Starting your hardy hibiscus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Zone 3b the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -35°F.

Since the USDA zone info for Zone 3b is just an average the actual date of last frost changes from year to year. Since half of the time in Zone 3b there is a last frost after May 15 be ready to protect your hardy hibiscus if you have a surprise late frost.

USDA Zone Info for Zone 3b

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Zone 3b

You may be interested in your other planting guides for Zone 3b.