Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when you can plant hypericum by checking out the USDA zone info for Napa.

Planting Calendar for Hypericum

Frost tolerance for hypericum:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Hypericum do ok in moderate cold which tells us that you can start planting them slightly earlier than more sensitive plants.

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

Last Frost Date

On average the last frost has passed is on February 15 in Napa. You can expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that USDA zone info for Napa may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Napa you get surprised by a frost after February 15 be ready to cover your hypericum in the event of a late frost.

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.