When to Plant Phlox in Zone 3b

One of the first steps you take when you are estimating your gardening schedule is find your 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.

The USDA zone info for Zone 3b can be looked at to estimate when it's the best time to plant phlox.


Planting Calendar for Phlox

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

Since phlox do well in moderate cold you can plant them a little earlier in the year than other plants that might not handle the cold.

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 Zone 3b 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 phlox and expect a good harvest is probably August. Any later than that and your phlox may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your phlox indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 3b. It might get as low as -35°F during the coldest months of winter.

Since the USDA zone info for Zone 3b is not always accurate the actual date of last frost is different every year. Since half of the time in Zone 3b you get surprised by a frost after May 15 be ready to cover your phlox in the event of one of those late frosts.

USDA Zone Info for Zone 3b

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-35°F
Highest Expected Low-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Zone 3b

You may be interested in your other planting guides for Zone 3b.