One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of estimating when you can plant penstemon is to examine the USDA zone info for Harriman.

Planting Calendar for Penstemon

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

Penstemon do ok in mild cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Harriman 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. You probably don't want to wait any later than that or else your penstemon may not have a chance to really do well. You can get started a couple of weeks earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is April 15 in Harriman. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Harriman is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Harriman last frost occurs after April 15 be ready to cover your penstemon if you have a late frost.

USDA Zone Info for Harriman

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 Harriman

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