One of the first steps you take when you are determining 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.

The USDA zone info for Duluth can be looked at to figure out when to plant liatris.

Planting Calendar for Liatris

Frost tolerance for liatris:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Liatris can survive in quite a bit of cold which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant liatris in Duluth is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant liatris and expect a good harvest is probably September. You probably don't want to wait any later than that or else your liatris may not have a chance to grow to maturity. Starting your liatris 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 Duluth. It might get as low as 5°F during the coldest months of winter.

Since the USDA zone info for Duluth is just an average the actual date of last frost changes from year to year. Half of the time in Duluth you get surprised by a frost after April 15 so be sure to be ready to cover your liatris in the event of a late frost.

USDA Zone Info for Duluth

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Duluth

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