Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when it's a good idea to plant astilbe by looking at the USDA zone info for Red Bluff.

Planting Calendar for Astilbe

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

You can plant astilbe a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant astilbe in Red Bluff 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 astilbe and expect a good harvest is probably September. If you wait any later than that and your astilbe may not have a chance to grow to maturity. Starting your astilbe indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Red Bluff. It might get as low as 25°F during the coldest months of winter.

It's important to remember that USDA zone info for Red Bluff is just an average and the actual date of last frost changes from year to year. Half of the time in Red Bluff there is a last frost after February 15 so be sure to be ready to protect your astilbe in the event of one of those late frosts.

USDA Zone Info for Red Bluff

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 Red Bluff

You may be interested in your other planting guides for Red Bluff.