One of the best tools that you have as gardeners to help us determine 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 USDA zone info for Merrill should be used to figure out when it's possible 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 are barely cold tolerant which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant verbena in Merrill 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 fully mature. Starting your verbena indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Merrill. In the coldest months of winter you should expect an average low temperature of -30°F.

Since the USDA zone info for Merrill is an average the actual date of last frost is different every year. Half of the time in Merrill you get a frost after May 15 so always be ready to cover your verbena in the event of a late frost.

USDA Zone Info for Merrill

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 Merrill

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