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 should be able to figure out when it's possible to plant periwinkles by referring to the USDA zone info for Winona.

Planting Calendar for Periwinkles

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

Since periwinkles do not do well in cold weather it is necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Winona 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 grow to maturity. You can get started a couple of weeks earlier by starting your periwinkles indoors.

Last Frost Date

In Winona the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 5°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Winona and it is different every year. Half of the time in Winona you get surprised by a frost after April 15 so make sure that you are prepared to cover your periwinkles in the event of a late frost.

USDA Zone Info for Winona

Here is the info for USDA Zone 7b.

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

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Winona

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