Before planting it is a good idea to find your USDA Zone info to estimate your garden 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 Livermore can be used to estimate when you can 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.

Periwinkles require warm weather which tells us that you have to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Livermore 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 grow to maturity. Starting your periwinkles indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Livermore. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Livermore is just an average the actual date of last frost will vary from year to year. Since half of the time in Livermore it frosts late in the year after February 15 be ready to protect your periwinkles in the event of a surprise late frost.

USDA Zone Info for Livermore

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 Livermore

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