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.

A way of figuring out when it's possible to plant campanula is to examine the USDA zone info for Walden.

Planting Calendar for Campanula

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

Campanula do well in moderate cold which tells us that you can start planting them earlier than other frost tender plants.

The earliest that you can plant campanula in Walden 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 campanula and expect a good harvest is probably September. Any later than that and your campanula may not have a chance to grow to maturity. If you are starting your campanula 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 April 15 in Walden. You can expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Walden and it can change quite a bit from year to year. Since half of the time in Walden it frosts late in the year after April 15 be ready to cover your campanula in the event of one of those late frosts.

USDA Zone Info for Walden

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 Walden

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