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

One way of getting a good idea when it's a good idea to plant calla lily is to use the USDA zone info for Portland.

Planting Calendar for Calla Lily

Frost tolerance for calla lily:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's a bad idea to plant calla lily until after the last frost when the weather gets warmer because they require warm weather.

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

The last month that you can plant calla lily and expect a good harvest is probably August. If you wait any later than that and your calla lily may not have a chance to grow to maturity. If you are starting your calla lily indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 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 may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Portland last frost occurs after April 15 so make sure that you are ready to cover your calla lily 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.