One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when you can plant calliopsis by looking at the USDA zone info for Lake Oswego.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since calliopsis do not do well in cold weather it is necessary 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 Lake Oswego 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 calliopsis and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calliopsis may not have a chance to grow to maturity. Starting your calliopsis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Lake Oswego. In the coldest months of winter you should expect an average low temperature of 15°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Lake Oswego and it can change quite a bit from year to year. Half of the time in Lake Oswego you get surprised by a frost after March 15 so be sure to be ready to protect your calliopsis in the event of a late frost.

USDA Zone Info for Lake Oswego

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 Lake Oswego

You may be interested in your other planting guides for Lake Oswego.