One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Clarks Summit you can estimate when it's a good idea to 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.

You can plant penstemon just a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant penstemon in Clarks Summit 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 fully mature. If you are starting your penstemon indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Clarks Summit the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Clarks Summit and it will vary from year to year. Half of the time in Clarks Summit there is a last frost after April 15 so make sure that you are prepared to protect your penstemon if you have a late frost.

USDA Zone Info for Clarks Summit

Here is the info for USDA Zone 6a.

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

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Clarks Summit

You may be interested in your other planting guides for Clarks Summit.