One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of making a decision about when to plant periwinkles is to use the USDA zone info for Somerset.

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 you really should wait until after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Somerset 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 few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Somerset. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Somerset is not always accurate and the actual date of last frost is different every year. Half of the time in Somerset it frosts late in the year after April 15 so make sure that you are ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Somerset

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 Somerset

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