When to Plant Phlox in Mill Creek, WA

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.

It's a good idea to estimate when it's the best time to plant phlox by looking at the USDA zone info for Mill Creek.


Planting Calendar for Phlox

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

You can plant phlox a bit earlier in the year because they are moderately cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant phlox
Possibly ok, but a risky time to plant phlox
Probably not a good time to plant phlox

The earliest that you can plant phlox in Mill Creek 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. You probably don't want to wait any later than that or else your phlox may not have a chance to really do well. If you are starting your phlox indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Mill Creek the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 15°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Mill Creek and it will vary from year to year. Since half of the time in Mill Creek you get a frost after March 15 be ready to cover your phlox if you have a surprise late frost.

USDA Zone Info for Mill Creek

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 Low15°F
Highest Expected Low20°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 Mill Creek

You may be interested in your other planting guides for Mill Creek.