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

In Rolla you can determine when you can plant penstemon by checking out the USDA zone info.

Planting Calendar for Penstemon

Frost tolerance for penstemon:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since penstemon do well in moderate cold you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant penstemon in Rolla is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant penstemon and expect a good harvest is probably September. You probably don't want to wait any later than that or else your penstemon may not have a chance to grow to maturity. If you are starting your penstemon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Rolla. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Rolla is not always accurate the actual date of last frost changes from year to year. Half of the time in Rolla it frosts late in the year after April 15 so always be ready to cover your penstemon if you have 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.