The USDA Zone info is a great tool for gardeners to help us estimate your gardening 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 campanula is to consult the USDA zone info for Duluth.

Planting Calendar for Campanula

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

You can plant campanula a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant campanula in Duluth 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. If you wait 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 little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Duluth. It might get as low as -30°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Duluth and it will vary from year to year. Since half of the time in Duluth last frost occurs after May 15 be ready to protect your campanula in the event of one of those late frosts.

USDA Zone Info for Duluth

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Duluth

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