The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Ottawa you will be able to determine when you can plant larkspur.

Planting Calendar for Larkspur

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

Larkspur are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them much earlier than more sensitive plants.

The earliest that you can plant larkspur in Ottawa is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant larkspur and expect a good harvest is probably September. You probably don't want to wait any later than that or else your larkspur may not have a chance to fully mature. Starting your larkspur indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Ottawa. You should expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that USDA zone info for Ottawa is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Ottawa you get a frost after April 15 be ready to cover your larkspur in the event of a late frost.

USDA Zone Info for Ottawa

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ottawa

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