One of the first steps you take when you are determining 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 USDA zone info for Yankton can be looked at to figure out when it's possible to plant tall phlox.

Planting Calendar for Tall Phlox

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

Tall Phlox do well in moderate cold which tells us that you can get them planted earlier than more sensitive plants.

The earliest that you can plant tall phlox in Yankton 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. Starting your tall phlox indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Yankton. In the coldest months of winter you can expect an average low temperature of -20°F.

Always keep in mind that USDA zone info for Yankton is just an average and the actual date of last frost will vary from year to year. Since half of the time in Yankton there is a last frost after April 15 be ready to cover your tall phlox in the event of one of those late frosts.

USDA Zone Info for Yankton

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 Yankton

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