One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Larkspur you should be able to estimate when it's the best time to plant periwinkles.

Planting Calendar for Periwinkles

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

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

The earliest that you can plant periwinkles in Larkspur 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. 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 few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Larkspur. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Larkspur and it will vary from year to year. Half of the time in Larkspur it frosts late in the year after February 15 so just be sure to be ready to protect your periwinkles in the event of a surprise late frost.

USDA Zone Info for Larkspur

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 Larkspur

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