One of the best tools that you have as gardeners to help us estimate 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 referring to the USDA zone info for Portland you will be able to estimate when to plant calliopsis.

Planting Calendar for Calliopsis

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

Since calliopsis are not cold tolerant it's important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant calliopsis 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 calliopsis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your calliopsis may not have a chance to grow to maturity. If you are starting your calliopsis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Portland. You can expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Portland is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Portland it frosts late in the year after February 15 be ready to protect your calliopsis if you have a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Portland

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