One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant arctotis in Helena should be estimated by looking at the USDA zone info.

Planting Calendar for Arctotis

Frost tolerance for arctotis:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Arctotis are moderately cold tolerant which tells us that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant arctotis 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 arctotis and expect a good harvest is probably September. If you wait any later than that and your arctotis may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your arctotis indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Helena is just an average the actual date of last frost will vary from year to year. Half of the time in Helena it frosts late in the year after March 15 so make sure that you are prepared to protect your arctotis 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.