One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of determining when you can plant hardy hibiscus is to consult the USDA zone info for Princeton.

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 tend to make it in cold weather which tells us that you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hardy hibiscus in Princeton 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. Starting your hardy hibiscus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Princeton. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Princeton is just an average the actual date of last frost changes from year to year. Half of the time in Princeton there is a last frost after May 15 so be sure to be ready to cover your hardy hibiscus if you have a late frost.

USDA Zone Info for Princeton

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 Princeton

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