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.

You can estimate when to plant periwinkles in Decatur by using the USDA zone info.

Planting Calendar for Periwinkles

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

It's a bad idea to plant periwinkles until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant periwinkles in Decatur 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 really do well. If you are starting your periwinkles indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Decatur the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Decatur and it will vary from year to year. Half of the time in Decatur there is a last frost after April 15 so be sure to be ready to cover your periwinkles if you have a late frost.

USDA Zone Info for Decatur

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 Decatur

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