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

By referring to the USDA zone info for Sulphur you will be able to estimate when it's the best time 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.

Since astilbe do ok in moderate cold you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant astilbe in Sulphur 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. Starting your astilbe indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Sulphur the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Sulphur is an average the actual date of last frost is different every year. Half of the time in Sulphur you get a frost after April 15 so be sure to be ready to cover your astilbe in the event of a surprise late frost.

USDA Zone Info for Sulphur

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Sulphur

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