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 Mount Washington should be looked at 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.

You can not plant polygonums until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant polygonums in Mount Washington 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. You probably don't want to wait any later than that or else your polygonums may not have a chance to grow to maturity. You can get started a little bit earlier by starting your polygonums indoors.

Last Frost Date

On average the last frost is on April 15 in Mount Washington. You should expect an average low temperature of -5°F in the coldest months of winter.

It's important to remember that USDA zone info for Mount Washington is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Mount Washington you get a frost after April 15 be ready to protect your polygonums if you have a late frost.

USDA Zone Info for Mount Washington

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Mount Washington

You may be interested in your other planting guides for Mount Washington.