One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Sheboygan you can figure out when it's the best time to plant periwinkles by reviewing the USDA zone info.

Planting Calendar for Periwinkles

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

Since periwinkles do not do well in cold weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant periwinkles in Sheboygan 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. If you are starting your periwinkles indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Sheboygan. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Sheboygan is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Sheboygan you get surprised by a frost after April 15 so just be sure to be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Sheboygan

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 Sheboygan

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