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.

The USDA zone info for Owasso can be looked at to figure out when you can plant penstemon.

Planting Calendar for Penstemon

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

You can plant penstemon a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant penstemon in Owasso 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. If you are starting your penstemon indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Owasso. In the coldest months of winter you should expect an average low temperature of 0°F.

Just be sure to remember that USDA zone info for Owasso is an average and the actual date of last frost will vary from year to year. Since half of the time in Owasso last frost occurs after April 15 be ready to protect your penstemon if you have one of those late frosts.

USDA Zone Info for Owasso

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 Owasso

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