Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's the best time to plant nolana by referring to the USDA zone info for Helena.

Planting Calendar for Nolana

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

Since nolana require warm weather you must wait until after the last frost before you can plant them.

The earliest that you can plant nolana 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 nolana and expect a good harvest is probably August. If you wait any later than that and your nolana may not have a chance to really do well. Starting your nolana indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Helena. You can expect an average low temperature of -25°F in 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 can change quite a bit 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 nolana if you have 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.