Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Tulsa should be read to figure out 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 do well in some cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Tulsa 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 fully mature. 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 Tulsa. In the coldest months of winter you should expect an average low temperature of 0°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Tulsa and it can change quite a bit from year to year. Half of the time in Tulsa you get surprised by a frost after April 15 so just be sure to be ready to protect your penstemon in the event of one of those late frosts.

USDA Zone Info for Tulsa

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 Tulsa

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