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.

One way of figuring out when it's possible to plant brunfelsia is to use the USDA zone info for Helena.

Planting Calendar for Brunfelsia

Frost tolerance for brunfelsia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since brunfelsia require warm weather it is important to wait until after the last frost when the weather gets warmer before you can plant them.

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

The last month that you can plant brunfelsia and expect a good harvest is probably August. If you wait any later than that and your brunfelsia may not have a chance to fully mature. Starting your brunfelsia indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on May 15 in Helena. You should expect an average low temperature of -25°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 is different every year. Half of the time in Helena it frosts late in the year after May 15 so be sure to be ready to protect your brunfelsia 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.