The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's the best time to plant missouri primrose by referring to the USDA zone info for Washington.

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 tend to make it in moderate cold which tells us that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant missouri primrose in Washington 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. You probably don't want to wait any later than that or else your missouri primrose may not have a chance to grow to maturity. If you are starting your missouri primrose indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Washington. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Washington may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Washington you get surprised by a frost after April 15 be ready to cover your missouri primrose if you have a late frost.

USDA Zone Info for Washington

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 Washington

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