One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's possible to plant dipladenia by looking at the USDA zone info for Redwood City.

Planting Calendar for Dipladenia

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

Dipladenia are not cold tolerant which means that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant dipladenia in Redwood City 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. If you wait any later than that and your dipladenia may not have a chance to really do well. If you are starting your dipladenia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Redwood City. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Redwood City is not always accurate the actual date of last frost changes from year to year. Half of the time in Redwood City it frosts late in the year after February 15 so just be sure to be ready to cover your dipladenia in the event of a surprise late frost.

USDA Zone Info for Redwood City

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 Redwood City

You may be interested in your other planting guides for Redwood City.