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

The earliest that you can plant campanula in Onalaska can be figured out by referring to the USDA zone info.

Planting Calendar for Campanula

Frost tolerance for campanula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since campanula are moderately cold tolerant you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant campanula 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 campanula and expect a good harvest is probably August. Any later than that and your campanula may not have a chance to grow to maturity. Starting your campanula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Onalaska. It might get as low as -25°F during the coldest months of winter.

Remember that USDA zone info for Onalaska is not always accurate and the actual date of last frost changes from year to year. Half of the time in Onalaska you get a frost after May 15 so be sure to be ready to cover your campanula if you have one of those late frosts.

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.