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 Shelbyville can be reviewed to estimate when you can plant periwinkles.

Planting Calendar for Periwinkles

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

You really shouldn't plant periwinkles until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant periwinkles in Shelbyville 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 couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Shelbyville. You can expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for Shelbyville is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Shelbyville you get a frost after April 15 so make sure that you are prepared to protect your periwinkles if you have a surprise late frost.

USDA Zone Info for Shelbyville

Here is the info for USDA Zone 6a.

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

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

Plants to Grow in Shelbyville

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