One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

It's a good idea to figure out when to plant dipladenia by reviewing the USDA zone info for Napa.

Planting Calendar for Dipladenia

Frost tolerance for dipladenia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Dipladenia are not cold tolerant which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant dipladenia 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 dipladenia and expect a good harvest is probably September. You probably don't want to wait any later than that or else your dipladenia may not have a chance to fully mature. If you are starting your dipladenia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Just be sure to remember that USDA zone info for Napa may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Napa you get surprised by a frost after February 15 so always be ready to protect your dipladenia in the event of a surprise 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.