One of the first steps you take when you are figuring out 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.

The USDA zone info for Clear Lake should be reviewed to estimate when to plant periwinkles.

Planting Calendar for Periwinkles

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

You really shouldn't plant periwinkles until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant periwinkles in Clear Lake 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. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

The average date of last frost is April 15 in Clear Lake. You should expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that USDA zone info for Clear Lake is an average and the actual date of last frost changes from year to year. Since half of the time in Clear Lake last frost occurs after April 15 be ready to cover your periwinkles in the event of a surprise late frost.

USDA Zone Info for Clear Lake

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 Clear Lake

You may be interested in your other planting guides for Clear Lake.