Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can figure out when you can plant creeping phlox in Helena by reviewing the USDA zone info.

Planting Calendar for Creeping Phlox

Frost tolerance for creeping phlox:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since creeping phlox are very cold tolerant you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant creeping phlox in Helena 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 creeping phlox and expect a good harvest is probably September. Any later than that and your creeping phlox may not have a chance to fully mature. Starting your creeping phlox indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Helena. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Helena is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Helena it frosts late in the year after March 15 so make sure that you are prepared to protect your creeping phlox in the event of a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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