One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of estimating when it's possible to plant cardinal flower is to consult the USDA zone info for Harrisburg.

Planting Calendar for Cardinal Flower

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

You should not plant cardinal flower until after all chance of frost has passed because they are not cold tolerant.

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. 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. In the coldest months of winter you can expect an average low temperature of -5°F.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Harrisburg and it will vary from year to year. Since half of the time in Harrisburg last frost occurs after April 15 be ready to cover your cardinal flower if you have a surprise late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Harrisburg

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