One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

By reviewing the USDA zone info for South Portland you should be able to estimate when it's the best time 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.

Liatris do well in quite a bit of cold which means that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant liatris in South 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. You probably don't want to wait any later than that or else your liatris may not have a chance to really do well. If you are starting your liatris indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for South Portland is just an average the actual date of last frost will vary from year to year. Half of the time in South Portland it frosts late in the year after April 15 so always be ready to cover your liatris if you have one of those late frosts.

USDA Zone Info for South Portland

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in South Portland

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