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.

By using the USDA zone info for Sonoma it's a good idea to estimate when it's the best time to plant missouri primrose.

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 a little bit of cold which tells us that you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant missouri primrose in Sonoma is January. However, you really should wait until February 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 October. Any later than that and your missouri primrose may not have a chance to grow to maturity. You can get started a little bit earlier by starting your missouri primrose indoors.

Last Frost Date

In Sonoma the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Sonoma and it is different every year. Half of the time in Sonoma there is a last frost after February 15 so always be ready to cover your missouri primrose in the event of one of those late frosts.

USDA Zone Info for Sonoma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Sonoma

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