One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Watertown you should be able to estimate when to plant pennisetum.

Planting Calendar for Pennisetum

Frost tolerance for pennisetum:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Pennisetum are one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant pennisetum in Watertown is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant pennisetum and expect a good harvest is probably August. If you wait any later than that and your pennisetum may not have a chance to fully mature. Starting your pennisetum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Watertown the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Watertown may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Watertown you get surprised by a frost after May 15 be ready to protect your pennisetum 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.