Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant achillea in Portland should be determined by using the USDA zone info.

Planting Calendar for Achillea

Frost tolerance for achillea:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Achillea do well in cold which means that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant achillea 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 achillea and expect a good harvest is probably September. You probably don't want to wait any later than that or else your achillea may not have a chance to grow to maturity. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Portland. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Portland is just an average the actual date of last frost is different every year. Since half of the time in Portland you get surprised by a frost after March 15 be ready to protect your achillea in the event of a late frost.

USDA Zone Info for Portland

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 Portland

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