One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

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

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 can survive in some cold which means that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant tall phlox in Rockwall 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. You probably don't want to wait any later than that or else your tall phlox may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your tall phlox indoors.

Last Frost Date

The average date of last frost is March 15 in Rockwall. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Rockwall is just an average the actual date of last frost will vary from year to year. Half of the time in Rockwall you get a frost after March 15 so make sure that you are ready to protect your tall phlox if you have a surprise late frost.

USDA Zone Info for Rockwall

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 Rockwall

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