The USDA Zone info is a great tool for gardeners to help us figure out your gardening 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 Grand Forks can be read 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.

Penstemon can survive in some cold which means that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant penstemon in Grand Forks 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. If you wait any later than that and your penstemon may not have a chance to really do well. 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 when the weather gets warmer is on May 15 in Grand Forks. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Grand Forks is an average the actual date of last frost changes from year to year. Since half of the time in Grand Forks there is a last frost after May 15 be ready to cover your penstemon if you have one of those late frosts.

USDA Zone Info for Grand Forks

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 Grand Forks

You may be interested in your other planting guides for Grand Forks.