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

You should be able to estimate when you can plant cardinal flower by checking out the USDA zone info for Zone 5b.

Planting Calendar for Cardinal Flower

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

Cardinal Flower are not cold tolerant which tells us that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant cardinal flower in Zone 5b 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 grow to maturity. Starting your cardinal flower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Zone 5b. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Zone 5b is an average and the actual date of last frost will vary from year to year. Half of the time in Zone 5b you get surprised by a frost after April 15 so make sure that you are ready to cover your cardinal flower in the event of a surprise late frost.

USDA Zone Info for Zone 5b

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Zone 5b

You may be interested in your other planting guides for Zone 5b.