One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Edwardsville can be reffered to in order to estimate when it's the best time to plant periwinkles.

Planting Calendar for Periwinkles

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

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

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Edwardsville. It might get as low as -5°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Edwardsville 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 Edwardsville last frost occurs after April 15 so make sure that you are ready to protect your periwinkles in the event of one of those late frosts.

USDA Zone Info for Edwardsville

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Edwardsville

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