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.

A way of estimating when it's a good idea to plant tall phlox is to examine the USDA zone info for Mandan.

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 a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant tall phlox in Mandan is March. However, you really should wait until April 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 August. You probably don't want to wait any later than that or else your tall phlox may not have a chance to fully mature. Starting your tall phlox indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Mandan the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Mandan may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Mandan there is a last frost after May 15 be ready to cover your tall phlox if you have a surprise late frost.

USDA Zone Info for Mandan

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Mandan

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