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.

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

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 do not do well in cold 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 Orinda 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. If you wait any later than that and 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

The average date of last frost is February 15 in Orinda. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Orinda is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Orinda you get a frost after February 15 be ready to protect your periwinkles in the event of a surprise late frost.

USDA Zone Info for Orinda

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 Orinda

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