Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when it's a good idea to plant penstemon is to examine the USDA zone info for Greenfield.

Planting Calendar for Penstemon

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

Penstemon are one of those plants that can tolerate a little bit of cold weather which means that you can get them planted earlier than more sensitive plants.

The earliest that you can plant penstemon in Greenfield 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 couple of weeks earlier.

Last Frost Date

In Greenfield 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.

Since the USDA zone info for Greenfield is not always accurate the actual date of last frost changes from year to year. Since half of the time in Greenfield it frosts late in the year after April 15 be ready to protect your penstemon in the event of a late frost.

USDA Zone Info for Greenfield

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 Greenfield

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