Before planting it is a good idea to find your USDA Zone info to estimate 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.

By using the USDA zone info for Marshfield you should be able to figure out when it's possible to plant ageratum.

Planting Calendar for Ageratum

Frost tolerance for ageratum:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You really shouldn't plant ageratum until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant ageratum in Marshfield 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 ageratum and expect a good harvest is probably August. Any later than that and your ageratum may not have a chance to grow to maturity. You can get started a little bit earlier by starting your ageratum indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Marshfield. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Marshfield may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Marshfield you get a frost after May 15 be ready to cover your ageratum in the event of a late frost.

USDA Zone Info for Marshfield

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 Marshfield

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