One of the first steps you take when you are getting a good idea 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.

By referring to the USDA zone info for Helena it's a good idea to figure out when it's possible to plant black eyed susans.

Planting Calendar for Black Eyed Susans

Frost tolerance for black eyed susans:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You should not plant black eyed susans until after the last frost has passed because they do not do well in cold weather.

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

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

Last Frost Date

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

Remember that USDA zone info for Helena may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Helena you get surprised by a frost after March 15 so be sure to be ready to cover your black eyed susans if you have one of those late frosts.

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.