One of the first steps you take when you are figuring out 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.

The first opportunity to plant hollyhocks in Billings should be estimated by referring to the USDA zone info.

Planting Calendar for Hollyhocks

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

Since hollyhocks are moderately cold tolerant you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hollyhocks 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 hollyhocks and expect a good harvest is probably August. Any later than that and your hollyhocks may not have a chance to grow to maturity. Starting your hollyhocks indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Billings. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Billings is just an average the actual date of last frost is different every year. Half of the time in Billings last frost occurs after May 15 so make sure that you are prepared to protect your hollyhocks if you have a 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.