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

The USDA zone info for Washington should be used to estimate when it's the best time to plant iberis.

Planting Calendar for Iberis

Frost tolerance for iberis:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Iberis do well in moderate cold which tells us that you can get them planted earlier than other frost tender plants.

The earliest that you can plant iberis in Washington is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant iberis and expect a good harvest is probably September. Any later than that and your iberis may not have a chance to really do well. If you are starting your iberis 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 April 15 in Washington. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Washington is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Washington there is a last frost after April 15 be ready to cover your iberis if you have one of those late frosts.

USDA Zone Info for Washington

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Washington

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