One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's a good idea to plant oxalis by referring to the USDA zone info for Missoula.

Planting Calendar for Oxalis

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

Oxalis are not cold tolerant which means that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant oxalis 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 oxalis and expect a good harvest is probably August. You probably don't want to wait any later than that or else your oxalis may not have a chance to grow to maturity. If you are starting your oxalis indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Missoula. In the coldest months of winter you should expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Missoula is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Missoula last frost occurs after April 15 so always be ready to cover your oxalis 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.