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.

By reviewing the USDA zone info for Bartlesville you will be able to determine when it's the best time to plant penstemon.

Planting Calendar for Penstemon

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

Penstemon can survive in moderate cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Bartlesville 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 grow to maturity. You can get started a little bit earlier by starting your penstemon indoors.

Last Frost Date

The average date of last frost is April 15 in Bartlesville. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Bartlesville is not always accurate the actual date of last frost is different every year. Half of the time in Bartlesville you get a frost after April 15 so make sure that you are ready to protect your penstemon in the event of one of those late frosts.

USDA Zone Info for Bartlesville

Here is the info for USDA Zone 6b.

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

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

Plants to Grow in Bartlesville

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