One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when it's possible to plant armeria is to refer to the USDA zone info for Rapid City.

Planting Calendar for Armeria

Frost tolerance for armeria:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant armeria much earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant armeria in Rapid City 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 armeria and expect a good harvest is probably September. You probably don't want to wait any later than that or else your armeria may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your armeria indoors.

Last Frost Date

The average date of last frost is April 15 in Rapid City. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Rapid City is just an average the actual date of last frost changes from year to year. Since half of the time in Rapid City you get surprised by a frost after April 15 be ready to cover your armeria in the event of a late frost.

USDA Zone Info for Rapid City

Here is the info for USDA Zone 5a.

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

Plants to Grow in Rapid City

You may be interested in your other planting guides for Rapid City.