One of the best tools that you have as gardeners to help us figure out 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.

The USDA zone info for Great Falls can be read to figure out when it's possible to plant dipladenia.

Planting Calendar for Dipladenia

Frost tolerance for dipladenia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since dipladenia do not do well in cold weather you have to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant dipladenia 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 dipladenia and expect a good harvest is probably August. Any later than that and your dipladenia may not have a chance to fully mature. If you are starting your dipladenia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Great Falls is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Great Falls there is a last frost after May 15 be ready to cover your dipladenia 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.