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.

The first opportunity to plant periwinkles in Winterset should be determined by reviewing the USDA zone info.

Planting Calendar for Periwinkles

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

You should not plant periwinkles until after the last frost because they do not do well in cold weather.

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

Last Frost Date

The average date of last frost is April 15 in Winterset. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Winterset is an average the actual date of last frost changes from year to year. Since half of the time in Winterset last frost occurs after April 15 be ready to protect your periwinkles in the event of one of those late frosts.

USDA Zone Info for Winterset

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Winterset

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