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

A common way of making a decision about when it's the best time to plant penstemon is to use the USDA zone info for Nashua.

Planting Calendar for Penstemon

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

Penstemon do well in moderate cold which means that you can get them planted earlier than more sensitive plants.

The earliest that you can plant penstemon in Nashua 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 few weeks earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is April 15 in Nashua. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Nashua is not always accurate and the actual date of last frost is different every year. Since half of the time in Nashua there is a last frost after April 15 be ready to cover your penstemon if you have one of those late frosts.

USDA Zone Info for Nashua

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Nashua

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