Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's the best time to plant periwinkles is to use the USDA zone info for Sulphur Springs.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Periwinkles require warm weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant periwinkles in Sulphur Springs 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 grow to maturity. Starting your periwinkles indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Sulphur Springs. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Sulphur Springs is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Sulphur Springs you get surprised by a frost after March 15 so make sure that you are prepared to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for Sulphur Springs

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Sulphur Springs

You may be interested in your other planting guides for Sulphur Springs.