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 estimate when you can plant diascia by reviewing the USDA zone info for Billings.

Planting Calendar for Diascia

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

Diascia do ok in some cold which means that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant diascia in Billings 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 diascia and expect a good harvest is probably August. Any later than that and your diascia may not have a chance to really do well. Starting your diascia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Billings. You should expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Billings and it changes from year to year. Half of the time in Billings it frosts late in the year after May 15 so make sure that you are prepared to cover your diascia in the event of one of those late frosts.

USDA Zone Info for Billings

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 Billings

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