The USDA Zone info is a great tool for gardeners to help us estimate 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 Elk River can be used to figure out when it's possible to plant polygonums.

Planting Calendar for Polygonums

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

Polygonums require warm weather which tells us that you really should wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant polygonums in Elk River 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 really do well. Starting your polygonums indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Elk River. It might get as low as -25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Elk River and it will vary from year to year. Half of the time in Elk River there is a last frost after May 15 so be sure to be ready to protect your polygonums in the event of a late frost.

USDA Zone Info for Elk River

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Elk River

You may be interested in your other planting guides for Elk River.