Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when it's the best time to plant penstemon by checking out the USDA zone info for Litchfield.

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 a little earlier in the year because they are moderately cold tolerant.

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

The last month that you can plant penstemon and expect a good harvest is probably August. You probably don't want to wait any later than that or else 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

On average the last frost is on May 15 in Litchfield. You can expect an average low temperature of -25°F in the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Litchfield and it will vary from year to year. Since half of the time in Litchfield it frosts late in the year after May 15 be ready to cover your penstemon in the event of one of those late frosts.

USDA Zone Info for Litchfield

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Litchfield

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