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.

The USDA zone info for Rolla should be used to determine when it's possible to plant blue throatwort.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant blue throatwort until after the last frost because they are not cold tolerant.

The earliest that you can plant blue throatwort in Rolla 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 blue throatwort and expect a good harvest is probably August. Any later than that and your blue throatwort may not have a chance to really do well. You can get started a couple of weeks earlier by starting your blue throatwort indoors.

Last Frost Date

In Rolla the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that USDA zone info for Rolla may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Rolla you get surprised by a frost after April 15 so always be ready to protect your blue throatwort in the event of a late frost.

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.