The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when to plant achillea in Thief River Falls by reviewing the USDA zone info.

Planting Calendar for Achillea

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

Achillea do well in a bit of cold which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant achillea in Thief River Falls is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant achillea and expect a good harvest is probably August. Any later than that and your achillea may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your achillea indoors.

Last Frost Date

In Thief River Falls the average date of last frost happens on May 15. It might get as low as -35°F during the coldest months of winter.

Since the USDA zone info for Thief River Falls may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Thief River Falls you get a frost after May 15 so always be ready to protect your achillea if you have a late frost.

USDA Zone Info for Thief River Falls

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Thief River Falls

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