The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 getting a good idea when it's possible to plant polygonums is to refer to the USDA zone info for Highland.

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 you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant polygonums in Highland is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant polygonums and expect a good harvest is probably September. If you wait any later than that and 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

The average date of last frost is February 15 in Highland. It might get as low as 25°F during the coldest months of winter.

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 Highland and it will vary from year to year. Since half of the time in Highland you get surprised by a frost after February 15 be ready to cover your polygonums if you have a late frost.

USDA Zone Info for Highland

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Highland

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