The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Rialto you can estimate when it's possible to plant astilbe by using the USDA zone info.

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 can survive in mild cold which means that you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant astilbe in Rialto 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. Any later than that and your astilbe may not have a chance to really do well. Starting your astilbe indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Rialto the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Rialto and it can change quite a bit from year to year. Half of the time in Rialto it frosts late in the year after January 31 so be sure to be ready to protect your astilbe if you have a late frost.

USDA Zone Info for Rialto

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Rialto

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