Before planting it is a good idea to find your USDA Zone info to figure out 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.

In Ravenna you can estimate when it's a good idea to plant penstemon by checking out 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.

Since penstemon do well in moderate cold you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant penstemon in Ravenna 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 really do well. You can get started a few weeks earlier by starting your penstemon indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Ravenna. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Ravenna is just an average the actual date of last frost changes from year to year. Half of the time in Ravenna there is a last frost after April 15 so be sure to be ready to protect your penstemon in the event of a surprise late frost.

USDA Zone Info for Ravenna

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 Ravenna

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