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.

You will be able to figure out when you can plant penstemon by using the USDA zone info for Carterville.

Planting Calendar for Penstemon

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

Penstemon can survive in some cold which means that you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant penstemon in Carterville 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. Any later than that and your penstemon may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your penstemon indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Carterville. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Carterville may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Carterville last frost occurs after April 15 so be sure to be ready to cover your penstemon in the event of a surprise late frost.

USDA Zone Info for Carterville

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 Carterville

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