The USDA Zone info is a great tool for gardeners to help us estimate your gardening 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 Bay City can be read to figure out 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 the last frost when the weather gets warmer.

Since periwinkles are not cold tolerant you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in Bay City is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant periwinkles and expect a good harvest is probably September. If you wait any later than that and your periwinkles may not have a chance to fully mature. You can get started a few weeks earlier by starting your periwinkles indoors.

Last Frost Date

In Bay City the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Bay City and it changes from year to year. Half of the time in Bay City it frosts late in the year after February 15 so always be ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Bay City

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

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

Plants to Grow in Bay City

You may be interested in your other planting guides for Bay City.