Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can figure out when it's a good idea to plant tropical hibiscus in Watertown by referring to the USDA zone info.

Planting Calendar for Tropical Hibiscus

Frost tolerance for tropical hibiscus:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Tropical Hibiscus require warm weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant tropical hibiscus 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 tropical hibiscus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tropical hibiscus may not have a chance to grow to maturity. If you are starting your tropical hibiscus 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 Watertown. In the coldest months of winter you can expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Watertown may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Watertown you get a frost after May 15 so just be sure to be ready to protect your tropical hibiscus 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.