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.

One way of making a decision about when you can plant catharanthus is to check out the USDA zone info for San Ramon.

Planting Calendar for Catharanthus

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

Since catharanthus require warm weather it is necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant catharanthus in San Ramon 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 catharanthus and expect a good harvest is probably September. Any later than that and your catharanthus may not have a chance to really do well. Starting your catharanthus indoors is a great way to get them started a little bit earlier.

Last Frost Date

In San Ramon the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for San Ramon and it can change quite a bit from year to year. Half of the time in San Ramon you get surprised by a frost after February 15 so make sure that you are ready to cover your catharanthus if you have a surprise late frost.

USDA Zone Info for San Ramon

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 San Ramon

You may be interested in your other planting guides for San Ramon.