One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when it's the best time to plant helianthemum is to consult the USDA zone info for Bozeman.

Planting Calendar for Helianthemum

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

You can plant helianthemum a little bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant helianthemum in Bozeman 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 helianthemum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your helianthemum may not have a chance to grow to maturity. You can get started a little bit earlier by starting your helianthemum indoors.

Last Frost Date

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

It's important to remember that USDA zone info for Bozeman is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Bozeman there is a last frost after May 15 so always be ready to protect your helianthemum in the event of a late frost.

USDA Zone Info for Bozeman

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 Bozeman

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