When to Plant Tall Phlox in Harwood Heights, IL

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

You will be able to figure out when you can plant tall phlox by referring to the USDA zone info for Harwood Heights.


Planting Calendar for Tall Phlox

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

You can plant tall phlox a little earlier in the year because they do well in moderate cold.

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 Harwood Heights 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. If you wait any later than that and your tall phlox may not have a chance to grow to maturity. Starting your tall phlox indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Harwood Heights the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Harwood Heights and it is different every year. Since half of the time in Harwood Heights you get surprised by a frost after April 15 be ready to protect your tall phlox if you have a surprise late frost.

USDA Zone Info for Harwood Heights

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°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 -10°F.

Plants to Grow in Harwood Heights

You may be interested in your other planting guides for Harwood Heights.