One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Douglas you can determine when you can plant polygonums by reviewing the USDA zone info.

Planting Calendar for Polygonums

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

You should 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 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 really do well. You can get started a couple of weeks earlier by starting your polygonums indoors.

Last Frost Date

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

Since the USDA zone info for Douglas may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Douglas you get surprised by a frost after March 15 so make sure that you are prepared to protect your polygonums in the event of one of those late frosts.

USDA Zone Info for Douglas

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 Douglas

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