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.

You should be able to figure out when to plant periwinkles by using the USDA zone info for Santa Clara.

Planting Calendar for Periwinkles

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

Since periwinkles are not cold tolerant it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Santa Clara 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 really do well. Starting your periwinkles indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Santa Clara. In the coldest months of winter you should expect an average low temperature of 25°F.

Keep in mind that USDA zone info for Santa Clara is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Santa Clara last frost occurs after February 15 be ready to cover your periwinkles in the event of one of those late frosts.

USDA Zone Info for Santa Clara

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 Santa Clara

You may be interested in your other planting guides for Santa Clara.