One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant tall phlox in Spearfish can be determined by looking at the USDA zone info.

Planting Calendar for Tall Phlox

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

You can plant tall phlox just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant tall phlox in Spearfish 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. Any later than that and your tall phlox may not have a chance to really do well. You can get started a few weeks earlier by starting your tall phlox indoors.

Last Frost Date

The average date of last frost is April 15 in Spearfish. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Spearfish is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Spearfish last frost occurs after April 15 so just be sure to be ready to cover your tall phlox if you have a late frost.

USDA Zone Info for Spearfish

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 Spearfish

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