Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Iron Mountain should be used to estimate when it's possible to plant four-o-clock flower.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since four-o-clock flower do not do well in cold weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four-o-clock flower in Iron Mountain 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 four-o-clock flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to really do well. You can get started a few weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Iron Mountain. In the coldest months of winter you should expect an average low temperature of -30°F.

Since the USDA zone info for Iron Mountain is just an average the actual date of last frost changes from year to year. Half of the time in Iron Mountain you get surprised by a frost after May 15 so just be sure to be ready to protect your four-o-clock flower in the event of a surprise late frost.

USDA Zone Info for Iron Mountain

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 Iron Mountain

You may be interested in your other planting guides for Iron Mountain.