Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when you can plant polygonums is to refer to the USDA zone info for Spearfish.

Planting Calendar for Polygonums

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

You should not plant polygonums until after the last frost because they require warm weather.

The earliest that you can plant polygonums in Spearfish is April. However, you really should wait until May 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 fully mature. 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 April 15 in Spearfish. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Spearfish is just an average and the actual date of last frost will vary from year to year. Half of the time in Spearfish you get a frost after April 15 so just be sure to be ready to cover your polygonums in the event of one of those late frosts.

USDA Zone Info for Spearfish

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Spearfish

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