Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of making a decision about when you can plant larkspur is to use the USDA zone info for Onalaska.

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 weather which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant larkspur in Onalaska 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. You probably don't want to wait any later than that or else your larkspur may not have a chance to really do well. If you are starting your larkspur indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Onalaska. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Onalaska is just an average the actual date of last frost is different every year. Half of the time in Onalaska last frost occurs after May 15 so just be sure to be ready to protect your larkspur if you have a surprise late frost.

USDA Zone Info for Onalaska

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 Onalaska

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