The USDA Zone info is a great tool for gardeners to help us figure out 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.

The USDA zone info for River Falls should be reffered to in order to determine when you can plant calla lily.

Planting Calendar for Calla Lily

Frost tolerance for calla lily:	Not tolerant of frost.
When to plant:	After the last frost.

Since calla lily do not do well in cold weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant calla lily in River Falls is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant calla lily and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calla lily may not have a chance to really do well. Starting your calla lily indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for River Falls is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in River Falls there is a last frost after May 15 be ready to protect your calla lily if you have one of those late frosts.

USDA Zone Info for River Falls

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 River Falls

You may be interested in your other planting guides for River Falls.