Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Jackson it's a good idea 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.

It's a bad idea to plant periwinkles until after the last frost because they do not do well in cold weather.

The earliest that you can plant periwinkles in Jackson is May. However, you really should wait until June 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. If you wait any later than that and your periwinkles may not have a chance to fully mature. 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 Jackson the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

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 Jackson and it changes from year to year. Since half of the time in Jackson it frosts late in the year after May 15 be ready to cover your periwinkles in the event of one of those late frosts.

USDA Zone Info for Jackson

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Jackson

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