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 looking at the USDA zone info for Helena you will be able to figure out when to plant artemesia.

Planting Calendar for Artemesia

Frost tolerance for artemesia:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Artemesia are barely cold tolerant which tells us that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant artemesia in Helena is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant artemesia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your artemesia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your artemesia indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Helena. In the coldest months of winter you can expect an average low temperature of 10°F.

It's important to 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 Helena and it is different every year. Since half of the time in Helena there is a last frost after March 15 be ready to cover your artemesia in the event of a surprise 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.