One of the first steps you take when you are determining your gardening schedule is find your 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.

In Round Rock you can figure out when it's a good idea to plant periwinkles by using 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 are not cold tolerant which means that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant periwinkles in Round Rock 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. If you wait any later than that and 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

In Round Rock the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Always keep in mind that USDA zone info for Round Rock is not always accurate and the actual date of last frost is different every year. Half of the time in Round Rock you get surprised by a frost after March 15 so just be sure to be ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Round Rock

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Round Rock

You may be interested in your other planting guides for Round Rock.