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

In Gretna you can estimate when it's possible to plant periwinkles by checking out the USDA zone info.

Planting Calendar for Periwinkles

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

Periwinkles require warm weather which means that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in Gretna 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. You probably don't want to wait any later than that or else 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

The average date of last frost is February 15 in Gretna. In the coldest months of winter you can expect an average low temperature of 25°F.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Gretna and it is different every year. Since half of the time in Gretna last frost occurs after February 15 be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Gretna

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Gretna

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