One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for International Falls you will be able to estimate when it's a good idea 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.

Since cardinal flower do not do well in cold weather you need to wait until after the last frost before you can plant them.

The earliest that you can plant cardinal flower in International Falls is May. However, you really should wait until June 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 grow to maturity. You can get started a little bit earlier by starting your cardinal flower indoors.

Last Frost Date

The average date of last frost is May 15 in International Falls. It might get as low as -40°F during the coldest months of winter.

Since the USDA zone info for International Falls is just an average the actual date of last frost will vary from year to year. Since half of the time in International Falls you get surprised by a frost after May 15 be ready to protect your cardinal flower in the event of a late frost.

USDA Zone Info for International Falls

Here is the info for USDA Zone 3a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-40°F
Highest Expected Low	-35°F

This means that on a really cold year, the coldest it will get is -40°F. On most years you should be prepared to experience lows near -35°F.

Plants to Grow in International Falls

You may be interested in your other planting guides for International Falls.