Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Rolla you can estimate when it's possible to plant verbena by using the USDA zone info.

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 moderate cold which means that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant verbena in Rolla 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 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. Starting your verbena indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Rolla. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Rolla is an average the actual date of last frost is different every year. Half of the time in Rolla you get a frost after April 15 so just be sure to be ready to protect your verbena in the event of one of those late frosts.

USDA Zone Info for Rolla

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Rolla

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