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.

In Ellensburg you can figure out when to plant periwinkles by referring to the USDA zone info.

Planting Calendar for Periwinkles

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

Since periwinkles do not do well in cold weather it is important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in Ellensburg 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. If you wait any later than that and your periwinkles may not have a chance to fully mature. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

In Ellensburg the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Ellensburg may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Ellensburg there is a last frost after April 15 be ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Ellensburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Ellensburg

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