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.

The USDA zone info for Scottsdale should be reviewed to figure out when you can plant astilbe.

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.

Astilbe do ok in moderate cold which means that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant astilbe in Scottsdale 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. You probably don't want to wait any later than that or else your astilbe may not have a chance to really do well. Starting your astilbe indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Scottsdale. You can expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Scottsdale and it can change quite a bit from year to year. Half of the time in Scottsdale there is a last frost after February 15 so always be ready to cover your astilbe in the event of a surprise late frost.

USDA Zone Info for Scottsdale

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 Scottsdale

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