One of the best tools that you have as gardeners to help us estimate 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.

One way of getting a good idea when it's the best time to plant periwinkles is to examine the USDA zone info for Steilacoom.

Planting Calendar for Periwinkles

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

It's a bad idea to plant periwinkles until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant periwinkles in Steilacoom is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant periwinkles and expect a good harvest is probably August. You probably don't want to wait any later than that or else your periwinkles may not have a chance to really do well. You can get started a couple of weeks earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Steilacoom. It might get as low as 15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Steilacoom is just an average and the actual date of last frost changes from year to year. Since half of the time in Steilacoom you get a frost after March 15 be ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Steilacoom

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Steilacoom

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