One of the best tools that you have as gardeners to help us figure out 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 to plant ageratum by reviewing the USDA zone info for Rohnert Park.

Planting Calendar for Ageratum

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

Since ageratum are not cold tolerant you must wait until after the last frost has passed before you can plant them.

The earliest that you can plant ageratum in Rohnert Park 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 ageratum and expect a good harvest is probably September. If you wait any later than that and your ageratum may not have a chance to fully mature. Starting your ageratum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Rohnert Park. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that USDA zone info for Rohnert Park is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Rohnert Park you get a frost after February 15 so make sure that you are prepared to cover your ageratum if you have a surprise late frost.

USDA Zone Info for Rohnert Park

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 Rohnert Park

You may be interested in your other planting guides for Rohnert Park.