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.

You can figure out when it's the best time to plant hardy hibiscus in Philadelphia by looking at 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.

Since hardy hibiscus are one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant hardy hibiscus in Philadelphia is February. However, you really should wait until March 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 September. If you wait any later than that and your hardy hibiscus may not have a chance to fully mature. You can get started a few weeks earlier by starting your hardy hibiscus indoors.

Last Frost Date

The average date of last frost is April 15 in Philadelphia. In the coldest months of winter you should expect an average low temperature of 0°F.

Since the USDA zone info for Philadelphia is just an average the actual date of last frost will vary from year to year. Since half of the time in Philadelphia there is a last frost after April 15 be ready to cover your hardy hibiscus if you have a late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Philadelphia

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