Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when to plant periwinkles by checking out the USDA zone info for Clarks Summit.

Planting Calendar for Periwinkles

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

You really shouldn't plant periwinkles until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant periwinkles in Clarks Summit 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 really do well. You can get started a few weeks earlier by starting your periwinkles indoors.

Last Frost Date

The average date of last frost is April 15 in Clarks Summit. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Clarks Summit is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Clarks Summit it frosts late in the year after April 15 so make sure that you are prepared to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Clarks Summit

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 Clarks Summit

You may be interested in your other planting guides for Clarks Summit.