One of the first steps you take when you are making a decision about 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 estimate when you can plant campanula in Portland by looking at the USDA zone info.

Planting Calendar for Campanula

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

You can plant campanula just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant campanula 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 campanula and expect a good harvest is probably September. If you wait any later than that and your campanula may not have a chance to really do well. You can get started a little bit earlier by starting your campanula indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portland. It might get as low as -15°F during the coldest months of winter.

It's important to remember that USDA zone info for Portland is just an average and the actual date of last frost changes from year to year. Half of the time in Portland it frosts late in the year after April 15 so be sure to be ready to protect your campanula 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.