Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 Kirkland it's a good idea to figure out when it's possible to plant periwinkles.

Planting Calendar for Periwinkles

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

Since periwinkles do not do well in cold weather you must wait until after the last frost before you can plant them.

The earliest that you can plant periwinkles in Kirkland 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. Any later than that and your periwinkles may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your periwinkles indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Kirkland. In the coldest months of winter you should expect an average low temperature of 15°F.

It's important to remember that USDA zone info for Kirkland is not always accurate and the actual date of last frost is different every year. Half of the time in Kirkland it frosts late in the year after March 15 so be sure to be ready to cover your periwinkles in the event of a late frost.

USDA Zone Info for Kirkland

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 Kirkland

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