One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant tall phlox in Watertown by looking at the USDA zone info.

Planting Calendar for Tall Phlox

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

Tall Phlox tend to make it in mild cold which tells us 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 tall phlox in Watertown 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. If you wait any later than that and your tall phlox may not have a chance to fully mature. Starting your tall 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 May 15 in Watertown. In the coldest months of winter you should expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Watertown is an average and the actual date of last frost will vary from year to year. Half of the time in Watertown last frost occurs after May 15 so make sure that you are prepared to protect your tall phlox if you have one of those late frosts.

USDA Zone Info for Watertown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Watertown

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