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.

One way of figuring out when it's a good idea to plant iberis is to examine the USDA zone info for Philadelphia.

Planting Calendar for Iberis

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

You can plant iberis a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant iberis 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 iberis and expect a good harvest is probably September. Any later than that and your iberis may not have a chance to grow to maturity. If you are starting your iberis indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Philadelphia may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Philadelphia it frosts late in the year after April 15 be ready to cover your iberis in the event of one of those late frosts.

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.