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 it's a good idea to determine when to plant liatris.

Planting Calendar for Liatris

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

You can plant liatris much earlier in the year because they do well in cold.

The earliest that you can plant liatris in Portland 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. If you wait any later than that and 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

In Portland the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 15°F.

Always keep in mind that USDA zone info for Portland is an average and the actual date of last frost will vary from year to year. Half of the time in Portland last frost occurs after March 15 so make sure that you are ready to protect your liatris if you have a late frost.

USDA Zone Info for Portland

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 Portland

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