One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Oregon you should be able to determine when it's possible to plant calla lily.

Planting Calendar for Calla Lily

Frost tolerance for calla lily:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since calla lily require warm weather you need to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant calla lily in Oregon 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. Any later than that and your calla lily may not have a chance to grow to maturity. You can get started a little bit earlier by starting your calla lily indoors.

Last Frost Date

The average date of last frost is April 15 in Oregon. You should expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Oregon and it is different every year. Since half of the time in Oregon you get surprised by a frost after April 15 be ready to cover your calla lily if you have a surprise late frost.

USDA Zone Info for Oregon

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Oregon

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