One of the first steps you take when you are determining 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.

You will be able to determine when it's possible to plant xerianthemum by referring to the USDA zone info for Billings.

Planting Calendar for Xerianthemum

Frost tolerance for xerianthemum:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since xerianthemum are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant xerianthemum in Billings 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 xerianthemum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your xerianthemum may not have a chance to really do well. Starting your xerianthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Billings is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Billings last frost occurs after May 15 be ready to cover your xerianthemum if you have a surprise late frost.

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.