The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Phoenix you can estimate when to plant penstemon by reviewing the USDA zone info.

Planting Calendar for Penstemon

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

Penstemon are moderately cold tolerant which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant penstemon in Phoenix 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 couple of weeks earlier by starting your penstemon indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Phoenix. It might get as low as 10°F during the coldest months of winter.

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

USDA Zone Info for Phoenix

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Phoenix

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