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

One way of figuring out when it's possible to plant bishop's weed is to examine the USDA zone info for Great Falls.

Planting Calendar for Bishop's Weed

Frost tolerance for bishop's weed:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Bishop's Weed do well in cold weather which means that you can plant them quite a bit earlier in the year than other frost tender plants.

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

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.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Great Falls and it changes from year to year. Half of the time in Great Falls there is a last frost after May 15 so make sure that you are ready to cover your bishop's weed if you have a surprise 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.