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.

By referring to the USDA zone info for Philadelphia you will be able to determine when it's a good idea to plant doronicum.

Planting Calendar for Doronicum

Frost tolerance for doronicum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Doronicum are moderately cold tolerant which tells us that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant doronicum 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 doronicum and expect a good harvest is probably September. If you wait any later than that and your doronicum may not have a chance to fully mature. If you are starting your doronicum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Philadelphia the average date of last frost happens on March 15. You should expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Philadelphia is just an average the actual date of last frost is different every year. Since half of the time in Philadelphia it frosts late in the year after March 15 be ready to cover your doronicum if you have a surprise late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Philadelphia

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