One of the best tools that you have as gardeners to help us estimate 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.

The best time to plant tall phlox in Pierre should be figured out by using 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.

Since tall phlox do well in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant tall phlox in Pierre 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. Any later than that and your tall phlox may not have a chance to really do well. 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

The average date of last frost is May 15 in Pierre. It might get as low as -25°F during the coldest months of winter.

It's important to remember that USDA zone info for Pierre is an average and the actual date of last frost is different every year. Half of the time in Pierre it frosts late in the year after May 15 so make sure that you are ready to cover your tall phlox in the event of a surprise late frost.

USDA Zone Info for Pierre

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Pierre

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