Before planting it is a good idea to find your USDA Zone info to figure out 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.

A common way of making a decision about when to plant astilbe is to examine the USDA zone info for Humble.

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 are one of those plants that can tolerate a tiny bit of cold weather which means that you can get them planted just a bit earlier than more sensitive plants.

The earliest that you can plant astilbe in Humble 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 grow to maturity. If you are starting your astilbe indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Humble the average date of last frost happens on February 15. It might get as low as 20°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 Humble and it is different every year. Half of the time in Humble there is a last frost after February 15 so be sure to be ready to cover your astilbe if you have a surprise late frost.

USDA Zone Info for Humble

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Humble

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