Before planting it is a good idea to find your USDA Zone info to figure out 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 first chance to plant polygonums in Castle Rock can be determined by reviewing the USDA zone info.

Planting Calendar for Polygonums

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

You really shouldn't plant polygonums until after all chance of frost has passed because they require warm weather.

The earliest that you can plant polygonums in Castle Rock 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. You probably don't want to wait any later than that or else your polygonums may not have a chance to really do well. If you are starting your polygonums indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Castle Rock. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Castle Rock may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Castle Rock you get surprised by a frost after April 15 so just be sure to be ready to protect your polygonums in the event of a surprise late frost.

USDA Zone Info for Castle Rock

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Castle Rock

You may be interested in your other planting guides for Castle Rock.