One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant erysimum in Billings should be determined by looking at the USDA zone info.

Planting Calendar for Erysimum

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

Erysimum tend to make it in some cold which tells us that you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant erysimum 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 erysimum and expect a good harvest is probably August. If you wait any later than that and your erysimum may not have a chance to grow to maturity. If you are starting your erysimum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Billings. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Billings is an average the actual date of last frost will vary from year to year. Since half of the time in Billings you get a frost after May 15 be ready to protect your erysimum 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.