One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when it's a good idea to plant achillea by referring to the USDA zone info for Zone 9b.

Planting Calendar for Achillea

Frost tolerance for achillea:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Achillea tend to make it in cold weather which tells us that you can plant them a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant achillea in Zone 9b is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant achillea and expect a good harvest is probably October. You probably don't want to wait any later than that or else your achillea may not have a chance to grow to maturity. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Zone 9b the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 9b and it is different every year. Half of the time in Zone 9b you get a frost after February 15 so always be ready to cover your achillea in the event of one of those late frosts.

USDA Zone Info for Zone 9b

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 Zone 9b

You may be interested in your other planting guides for Zone 9b.