One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to estimate when it's possible to plant periwinkles by using the USDA zone info for Austin.

Planting Calendar for Periwinkles

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

Periwinkles are not cold tolerant which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant periwinkles in Austin 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 little bit earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Austin. You can expect an average low temperature of -25°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Austin and it can change quite a bit from year to year. Half of the time in Austin it frosts late in the year after May 15 so always be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Austin

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 Austin

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