Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when it's the best time to plant polygonums is to consult the USDA zone info for Corvallis.

Planting Calendar for Polygonums

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

It's probably not a good idea to plant polygonums until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant polygonums in Corvallis 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 grow to maturity. If you are starting your polygonums indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Corvallis the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 15°F.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Corvallis and it will vary from year to year. Since half of the time in Corvallis there is a last frost after March 15 be ready to protect your polygonums in the event of a late frost.

USDA Zone Info for Corvallis

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

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

Plants to Grow in Corvallis

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