The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of making a decision about when it's the best time to plant polygonums is to refer to the USDA zone info for Bellingham.

Planting Calendar for Polygonums

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

Polygonums are not cold tolerant which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant polygonums in Bellingham 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. You can get started a few weeks earlier by starting your polygonums indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Bellingham. You should expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Bellingham is an average the actual date of last frost is different every year. Since half of the time in Bellingham it frosts late in the year after March 15 be ready to cover your polygonums if you have one of those late frosts.

USDA Zone Info for Bellingham

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Bellingham

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