Before planting it is a good idea to find your USDA Zone info to determine 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 estimate when it's possible to plant penstemon by referring to the USDA zone info for Stamford.

Planting Calendar for Penstemon

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

Penstemon tend to make it in mild cold which means that you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant penstemon in Stamford 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. 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

On average all chance of frost has passed is on April 15 in Stamford. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Stamford is not always accurate the actual date of last frost changes from year to year. Since half of the time in Stamford last frost occurs after April 15 be ready to cover your penstemon if you have a surprise late frost.

USDA Zone Info for Stamford

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Stamford

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