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.

A common way of figuring out when it's a good idea to plant euphorbia is to consult the USDA zone info for Riverside.

Planting Calendar for Euphorbia

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

Euphorbia are barely cold tolerant which means that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant euphorbia in Riverside 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 euphorbia and expect a good harvest is probably September. If you wait any later than that and your euphorbia may not have a chance to fully mature. If you are starting your euphorbia 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 Riverside. It might get as low as 25°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Riverside is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Riverside you get a frost after February 15 be ready to cover your euphorbia in the event of a surprise late frost.

USDA Zone Info for Riverside

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 Riverside

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