The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant penstemon in Shelbyville should be figured out by referring to 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 are moderately cold tolerant you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Shelbyville 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 grow to maturity. Starting your penstemon indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Shelbyville. In the coldest months of winter you should expect an average low temperature of -10°F.

Remember that USDA zone info for Shelbyville is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Shelbyville there is a last frost after April 15 so make sure that you are ready to cover your penstemon in the event of one of those late frosts.

USDA Zone Info for Shelbyville

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 Shelbyville

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