One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of making a decision about when you can plant polygonums is to examine the USDA zone info for Douglas.

Planting Calendar for Polygonums

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

It's probably not a good idea to plant polygonums until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant polygonums in Douglas 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 little bit earlier by starting your polygonums indoors.

Last Frost Date

The average date of last frost is March 15 in Douglas. You should expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Douglas is just an average the actual date of last frost is different every year. Half of the time in Douglas you get surprised by a frost after March 15 so be sure to be ready to protect your polygonums if you have a surprise late frost.

USDA Zone Info for Douglas

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 Douglas

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