One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's possible to plant polygonums in Mandan by using the USDA zone info.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After the last frost.

Since polygonums do not do well in cold weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant polygonums in Mandan is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant polygonums and expect a good harvest is probably August. Any later than that and your polygonums may not have a chance to really do well. Starting your polygonums indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Mandan. It might get as low as -30°F during the coldest months of winter.

Keep in mind that USDA zone info for Mandan is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Mandan you get a frost after May 15 so always be ready to cover your polygonums in the event of one of those late frosts.

USDA Zone Info for Mandan

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 Mandan

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