Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Raritan you should be able to estimate when it's possible to 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.

You can plant astilbe a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant astilbe in Raritan 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 astilbe and expect a good harvest is probably August. Any later than that and your astilbe may not have a chance to fully mature. You can get started a few weeks earlier by starting your astilbe indoors.

Last Frost Date

In Raritan the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Raritan and it can change quite a bit from year to year. Half of the time in Raritan you get surprised by a frost after April 15 so always be ready to cover your astilbe in the event of one of those late frosts.

USDA Zone Info for Raritan

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Raritan

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