Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when you can plant iberis is to use the USDA zone info for Portland.

Planting Calendar for Iberis

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

You can plant iberis a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant iberis in Portland 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. Starting your iberis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Portland. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Portland is an average the actual date of last frost will vary from year to year. Half of the time in Portland it frosts late in the year after April 15 so make sure that you are prepared to cover your iberis in the event of a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 5b.

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

Plants to Grow in Portland

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