One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant penstemon in Bismarck can be figured out by referring to 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.

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

The earliest that you can plant penstemon in Bismarck is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant penstemon and expect a good harvest is probably August. Any later than that and your penstemon may not have a chance to grow to maturity. Starting your penstemon indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Bismarck. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Bismarck is an average the actual date of last frost changes from year to year. Half of the time in Bismarck last frost occurs after May 15 so make sure that you are prepared to protect your penstemon in the event of a late frost.

USDA Zone Info for Bismarck

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Bismarck

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