One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of estimating when to plant periwinkles is to use the USDA zone info for Bristol.

Planting Calendar for Periwinkles

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

Since periwinkles are not cold tolerant it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in Bristol 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. 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 Bristol the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Keep in mind that USDA zone info for Bristol is just an average and the actual date of last frost changes from year to year. Since half of the time in Bristol there is a last frost after April 15 be ready to protect your periwinkles in the event of a late frost.

USDA Zone Info for Bristol

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 Bristol

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