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.

By referring to the USDA zone info for Duluth it's a good idea to determine when it's possible to plant polygonums.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

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

The earliest that you can plant polygonums in Duluth 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. If you wait any later than that and your polygonums may not have a chance to grow to maturity. Starting your polygonums indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Duluth the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Duluth may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Duluth it frosts late in the year after May 15 be ready to cover your polygonums in the event of a late frost.

USDA Zone Info for Duluth

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 Duluth

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