Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Lake Oswego you can estimate when it's possible to plant liatris by using the USDA zone info.

Planting Calendar for Liatris

Frost tolerance for liatris:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Liatris are very cold tolerant which means that you can get them planted much earlier than other plants that might not handle the cold.

The earliest that you can plant liatris in Lake Oswego 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 liatris and expect a good harvest is probably September. You probably don't want to wait any later than that or else your liatris may not have a chance to fully mature. You can get started a little bit earlier by starting your liatris indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Lake Oswego. You should expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Lake Oswego is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Lake Oswego last frost occurs after March 15 so be sure to be ready to cover your liatris if you have a surprise 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.