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.

It's possible to figure out when it's possible to plant larkspur by looking at the USDA zone info for Lisle.

Planting Calendar for Larkspur

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

You can plant larkspur earlier in the year because they do well in cold.

The earliest that you can plant larkspur in Lisle 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. 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

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

Since the USDA zone info for Lisle is just an average the actual date of last frost will vary from year to year. Half of the time in Lisle last frost occurs after April 15 so always be ready to cover your larkspur if you have a surprise late frost.

USDA Zone Info for Lisle

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Lisle

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