Before planting it is a good idea to find your USDA Zone info to figure out 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.

By using the USDA zone info for Harrisburg you should be able to determine when 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.

It's probably a bad idea to plant cardinal flower until after the last frost has passed because they require warm weather.

The earliest that you can plant cardinal flower in Harrisburg 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. You probably don't want to wait any later than that or else 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 little bit earlier.

Last Frost Date

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

Since the USDA zone info for Harrisburg is an average the actual date of last frost is different every year. Half of the time in Harrisburg there is a last frost after April 15 so just be sure to be ready to protect your cardinal flower if you have a surprise late frost.

USDA Zone Info for Harrisburg

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 Harrisburg

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