One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

In Great Falls you can figure out when it's a good idea to plant tritoma by checking out the USDA zone info.

Planting Calendar for Tritoma

Frost tolerance for tritoma:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since tritoma are one of those plants that can tolerate quite a bit of cold weather you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant tritoma in Great Falls 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 tritoma and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tritoma may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your tritoma indoors.

Last Frost Date

In Great Falls the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Remember that USDA zone info for Great Falls is not always accurate and the actual date of last frost is different every year. Half of the time in Great Falls it frosts late in the year after May 15 so just be sure to be ready to cover your tritoma in the event of a late frost.

USDA Zone Info for Great Falls

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Great Falls

You may be interested in your other planting guides for Great Falls.