Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when to plant larkspur is to consult the USDA zone info for Watertown.

Planting Calendar for Larkspur

Frost tolerance for larkspur:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Larkspur do well in cold which means that you can get them planted much earlier than other frost tender plants.

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

Last Frost Date

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

Since the USDA zone info for Watertown is not always accurate the actual date of last frost changes from year to year. Half of the time in Watertown you get a frost after May 15 so make sure that you are ready to cover your larkspur in the event of a surprise late frost.

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.