One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when it's the best time to plant penstemon by reviewing the USDA zone info for Clarksville.

Planting Calendar for Penstemon

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

Since penstemon are one of those plants that can tolerate a little bit of cold weather you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Clarksville 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. If you wait any later than that and your penstemon may not have a chance to fully mature. You can get started a little bit earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is April 15 in Clarksville. In the coldest months of winter you can expect an average low temperature of 5°F.

Remember that USDA zone info for Clarksville is not always accurate and the actual date of last frost is different every year. Since half of the time in Clarksville it frosts late in the year after April 15 be ready to protect your penstemon if you have one of those late frosts.

USDA Zone Info for Clarksville

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Clarksville

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