Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Thief River Falls it's possible to determine when it's a good idea to plant verbena.

Planting Calendar for Verbena

Frost tolerance for verbena:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Verbena do ok in very little cold which tells us that you can plant them slightly earlier in the year than other plants that might not handle the cold.

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

The last month that you can plant verbena and expect a good harvest is probably August. Any later than that and your verbena may not have a chance to grow to maturity. You can get started a little bit earlier by starting your verbena indoors.

Last Frost Date

The average date of last frost is May 15 in Thief River Falls. In the coldest months of winter you should expect an average low temperature of -35°F.

It's important to remember that USDA zone info for Thief River Falls is just an average and the actual date of last frost changes from year to year. Half of the time in Thief River Falls you get surprised by a frost after May 15 so always be ready to cover your verbena 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.