The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant astilbe in Worland can be estimated by checking out 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.

Since astilbe do ok in moderate cold you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant astilbe in Worland is April. However, you really should wait until May 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 grow to maturity. You can get started a few weeks earlier by starting your astilbe indoors.

Last Frost Date

In Worland the average date of last frost happens on May 15. You can expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Worland is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Worland it frosts late in the year after May 15 be ready to protect your astilbe in the event of one of those late frosts.

USDA Zone Info for Worland

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Worland

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