Before planting it is a good idea to find your USDA Zone info to estimate 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.

A way of figuring out when it's possible to plant bougainvillea is to refer to the USDA zone info for Missoula.

Planting Calendar for Bougainvillea

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

You can not plant bougainvillea until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant bougainvillea 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 bougainvillea and expect a good harvest is probably August. Any later than that and your bougainvillea may not have a chance to grow to maturity. Starting your bougainvillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Missoula the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Missoula is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Missoula you get a frost after April 15 be ready to protect your bougainvillea in the event of a late frost.

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.