When can I plant Tall Phlox in Zone 3b

The USDA Zone info is a great tool for gardeners to help us figure out our gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

By reviewing the USDA zone info for Zone 3b you will be able to determine when it's a good idea to plant tall phlox.


Planting Calendar for Tall Phlox

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

Since tall phlox do well in moderate cold you can plant them just a bit earlier in the year than other frost tender plants.

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

The earliest that you can plant tall 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 tall phlox and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tall phlox may not have a chance to really do well. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

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.

Always keep in mind that our actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 3b and it will vary from year to year. Since half of the time in Zone 3b it frosts late in the year after May 15 be ready to protect your tall phlox if we have 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 our other planting guides for Zone 3b.