Before planting it is a good idea to find your USDA Zone info to estimate 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.

The best time to plant polygonums in Lake Oswego should be figured out by looking at the USDA zone info.

Planting Calendar for Polygonums

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

Since polygonums are not cold tolerant it's important to wait until after the last frost has passed before you can plant them.

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

Last Frost Date

The average date of last frost is March 15 in Lake Oswego. In the coldest months of winter you should expect an average low temperature of 15°F.

Always keep in mind that USDA zone info for Lake Oswego is just an average and the actual date of last frost is different every year. Since half of the time in Lake Oswego it frosts late in the year after March 15 be ready to protect your polygonums if you have one of those late frosts.

USDA Zone Info for Lake Oswego

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 Lake Oswego

You may be interested in your other planting guides for Lake Oswego.