One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's the best time to plant purple coneflower in Portland by referring to the USDA zone info.

Planting Calendar for Purple Coneflower

Frost tolerance for purple coneflower:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Purple Coneflower do ok in some cold which tells us that you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant purple coneflower in Portland is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant purple coneflower and expect a good harvest is probably August. Any later than that and your purple coneflower may not have a chance to really do well. You can get started a few weeks earlier by starting your purple coneflower indoors.

Last Frost Date

In Portland the average date of last frost happens on March 15. 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 March 15 so be sure to be ready to cover your purple coneflower if you have 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.