Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 it's a good idea to figure out when to plant coral bells.

Planting Calendar for Coral Bells

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

Coral Bells tend to make it in some cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant coral bells 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 coral bells and expect a good harvest is probably August. You probably don't want to wait any later than that or else your coral bells may not have a chance to really do well. You can get started a few weeks earlier by starting your coral bells indoors.

Last Frost Date

In Helena the average date of last frost happens on May 15. It might get as low as -25°F during 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 changes from year to year. Half of the time in Helena there is a last frost after May 15 so make sure that you are ready to protect your coral bells in the event of one of those late frosts.

USDA Zone Info for Helena

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Helena

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