One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when to plant argyranthemum by looking at the USDA zone info for Riverside.

Planting Calendar for Argyranthemum

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

It's probably not a good idea to plant argyranthemum until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant argyranthemum in Riverside 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 argyranthemum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your argyranthemum may not have a chance to really do well. If you are starting your argyranthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Riverside may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Riverside there is a last frost after February 15 be ready to protect your argyranthemum if you have one of those late frosts.

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.