One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

The first chance to plant calliopsis in Duluth can be determined by using the USDA zone info.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since calliopsis do not do well in cold weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant calliopsis 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 calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to really do well. Starting your calliopsis indoors is a great way to get them started a few 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.

Always keep in mind that USDA zone info for Duluth is an average and the actual date of last frost will vary from year to year. Since half of the time in Duluth it frosts late in the year after May 15 be ready to protect your calliopsis in the event of one of those late frosts.

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.