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.

The earliest that you can plant four-o-clock flower in Watertown should be determined by checking out the USDA zone info.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably not a good idea to plant four-o-clock flower until after the last frost has passed because they require warm weather.

The earliest that you can plant four-o-clock flower in Watertown is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant four-o-clock flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to really do well. Starting your four-o-clock flower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Watertown. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Watertown is an average the actual date of last frost will vary from year to year. Half of the time in Watertown it frosts late in the year after May 15 so always be ready to cover your four-o-clock flower if you have one of those late frosts.

USDA Zone Info for Watertown

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Watertown

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