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

A way of getting a good idea when it's a good idea to plant tall phlox is to look at the USDA zone info for Rapid City.

Planting Calendar for Tall Phlox

Frost tolerance for tall phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since tall phlox are moderately cold tolerant you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tall phlox 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 tall phlox and expect a good harvest is probably September. If you wait any later than that and your tall phlox may not have a chance to fully mature. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Rapid City the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Always keep in mind that USDA zone info for Rapid City is just an average and the actual date of last frost is different every year. Since half of the time in Rapid City it frosts late in the year after April 15 be ready to protect your tall phlox in the event of one of those late frosts.

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.