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.

You can determine when it's the best time to plant argyranthemum in Great Falls by using the USDA zone info.

Planting Calendar for Argyranthemum

Frost tolerance for argyranthemum:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's not a good idea to plant argyranthemum until after the last frost because they do not do well in cold weather.

The earliest that you can plant argyranthemum in Great Falls is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant argyranthemum and expect a good harvest is probably August. Any later than that and your argyranthemum may not have a chance to really do well. Starting your argyranthemum indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Great Falls. In the coldest months of winter you should expect an average low temperature of -30°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Great Falls and it can change quite a bit from year to year. Half of the time in Great Falls you get a frost after May 15 so make sure that you are ready to protect your argyranthemum in the event of 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.