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

A way of making a decision about when it's a good idea to plant liatris is to refer to the USDA zone info for Helena.

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 cold which tells us that you can get them planted much earlier than plants that are more sensitive to the cold.

The earliest that you can plant liatris in Helena 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. You can get started a little bit earlier by starting your liatris indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Helena. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Helena you get a frost after March 15 so be sure to be ready to protect your liatris in the event of a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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