One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can figure out when it's a good idea to plant cardinal flower in Napa by looking at the USDA zone info.

Planting Calendar for Cardinal Flower

Frost tolerance for cardinal flower:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You can not plant cardinal flower until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant cardinal flower in Napa is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant cardinal flower and expect a good harvest is probably September. Any later than that and your cardinal flower may not have a chance to fully mature. You can get started a little bit earlier by starting your cardinal flower indoors.

Last Frost Date

In Napa the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for Napa may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Napa there is a last frost after February 15 so make sure that you are ready to protect your cardinal flower if you have one of those late frosts.

USDA Zone Info for Napa

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 Napa

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