Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Philadelphia can be reffered to in order to estimate when to plant calliopsis.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since calliopsis do not do well in cold weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant calliopsis in Philadelphia is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to fully mature. Starting your calliopsis indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Philadelphia is not always accurate and the actual date of last frost changes from year to year. Half of the time in Philadelphia you get surprised by a frost after April 15 so always be ready to protect your calliopsis in the event of 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.