The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. 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 Missoula can be looked at to estimate when it's the best time to plant trailing portulaca.

Planting Calendar for Trailing Portulaca

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

It's not a good idea to plant trailing portulaca until after the last frost because they are not cold tolerant.

The earliest that you can plant trailing portulaca in Missoula is April. However, you really should wait until May 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 fully mature. You can get started a few weeks earlier by starting your trailing portulaca indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Missoula. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Missoula is an average the actual date of last frost will vary from year to year. Half of the time in Missoula there is a last frost after April 15 so be sure to be ready to cover your trailing portulaca in the event of one of those late frosts.

USDA Zone Info for Missoula

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Missoula

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