Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 Waukegan should be reffered to in order to figure out when to plant periwinkles.

Planting Calendar for Periwinkles

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

Periwinkles require warm weather which means that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Waukegan 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. You probably don't want to wait any later than that or else 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 couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Waukegan is not always accurate the actual date of last frost is different every year. Since half of the time in Waukegan it frosts late in the year after April 15 be ready to cover your periwinkles in the event of a surprise late frost.

USDA Zone Info for Waukegan

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 Waukegan

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