One of the best tools that you have as gardeners to help us estimate 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.

In Pomona you can determine when it's possible to plant catharanthus by referring to the USDA zone info.

Planting Calendar for Catharanthus

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

Since catharanthus are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant catharanthus in Pomona 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 catharanthus and expect a good harvest is probably September. Any later than that and your catharanthus may not have a chance to grow to maturity. You can get started a little bit earlier by starting your catharanthus indoors.

Last Frost Date

The average date of last frost is January 31 in Pomona. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Pomona may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Pomona you get surprised by a frost after January 31 so make sure that you are prepared to cover your catharanthus if you have a late frost.

USDA Zone Info for Pomona

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Pomona

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