One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Swarthmore should be reffered to in order to figure out when it's the best time to plant cardinal flower.

Planting Calendar for Cardinal Flower

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

Since cardinal flower are not cold tolerant it's important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant cardinal flower in Swarthmore 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 cardinal flower and expect a good harvest is probably August. If you wait any later than that and your cardinal flower may not have a chance to fully mature. Starting your cardinal flower indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Swarthmore is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Swarthmore it frosts late in the year after April 15 be ready to cover your cardinal flower if you have a late frost.

USDA Zone Info for Swarthmore

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 Swarthmore

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