One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

A way of estimating when it's a good idea to plant periwinkles is to examine the USDA zone info for Danville.

Planting Calendar for Periwinkles

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

It's not a good idea to plant periwinkles until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant periwinkles in Danville 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 grow to maturity. If you are starting your periwinkles indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Danville and it will vary from year to year. Since half of the time in Danville you get a frost after February 15 be ready to protect your periwinkles in the event of a late frost.

USDA Zone Info for Danville

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 Danville

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