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.

You can determine when it's a good idea to plant missouri primrose in Portland by using the USDA zone info.

Planting Calendar for Missouri Primrose

Frost tolerance for missouri primrose:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Missouri Primrose do well in a little bit of cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant missouri primrose in Portland is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant missouri primrose and expect a good harvest is probably September. If you wait any later than that and your missouri primrose may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your missouri primrose indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Portland. It might get as low as 15°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Portland and it will vary from year to year. Since half of the time in Portland it frosts late in the year after March 15 be ready to protect your missouri primrose in the event of a late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Portland

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