The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's a good idea to plant cardinal flower by referring to the USDA zone info for Duluth.

Planting Calendar for Cardinal Flower

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

You can not plant cardinal flower until after the last frost because they are not cold tolerant.

The earliest that you can plant cardinal flower in Duluth 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. If you wait any later than that and your cardinal flower may not have a chance to fully mature. If you are starting your cardinal flower indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Duluth. In the coldest months of winter you can expect an average low temperature of -30°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Duluth and it changes from year to year. Half of the time in Duluth you get a frost after May 15 so just be sure to be ready to protect your cardinal flower if you have a late frost.

USDA Zone Info for Duluth

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Duluth

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