Before planting it is a good idea to find your USDA Zone info to figure out 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.

In Hillsboro you can figure out when it's a good idea to plant phlox by using the USDA zone info.

Planting Calendar for Phlox

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

Phlox do ok in some cold which means that you can plant them a little earlier in the year than other plants that might not handle the cold.

The earliest that you can plant phlox in Hillsboro 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 phlox and expect a good harvest is probably September. If you wait any later than that and your phlox may not have a chance to fully mature. Starting your phlox indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Hillsboro. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Hillsboro is just an average the actual date of last frost is different every year. Half of the time in Hillsboro you get surprised by a frost after March 15 so be sure to be ready to protect your phlox in the event of one of those late frosts.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Hillsboro

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