The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when it's possible to plant periwinkles in Hillsboro by looking at the USDA zone info.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After the last frost.

It's a bad idea to plant periwinkles until after the last frost has passed because they require warm weather.

The earliest that you can plant periwinkles in Hillsboro 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 periwinkles and expect a good harvest is probably August. If you wait any later than that and your periwinkles may not have a chance to fully mature. If you are starting your periwinkles indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Hillsboro the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Remember that USDA zone info for Hillsboro may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Hillsboro last frost occurs after April 15 be ready to cover your periwinkles in the event of a late frost.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Hillsboro

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