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

You should be able to determine when it's the best time to plant trailing portulaca by using the USDA zone info for Bozeman.

Planting Calendar for Trailing Portulaca

Frost tolerance for trailing portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's a bad idea to plant trailing portulaca until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant trailing portulaca in Bozeman 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 trailing portulaca and expect a good harvest is probably August. If you wait any later than that and your trailing portulaca may not have a chance to really do well. If you are starting your trailing portulaca indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Bozeman the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Bozeman is an average the actual date of last frost will vary from year to year. Since half of the time in Bozeman you get surprised by a frost after May 15 be ready to cover your trailing portulaca in the event of one of those late frosts.

USDA Zone Info for Bozeman

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Bozeman

You may be interested in your other planting guides for Bozeman.