One of the first steps you take when you are estimating 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.

In Watertown you can determine when it's possible to plant calliopsis by checking out the USDA zone info.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After the last frost.

Calliopsis do not do well in cold weather which tells us that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant calliopsis 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 calliopsis and expect a good harvest is probably August. If you wait any later than that and your calliopsis may not have a chance to grow to maturity. You can get started a little bit earlier by starting your calliopsis indoors.

Last Frost Date

In Watertown the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Watertown is an average the actual date of last frost is different every year. Since half of the time in Watertown there is a last frost after April 15 be ready to cover your calliopsis in the event of a surprise late frost.

USDA Zone Info for Watertown

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Watertown

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