One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Waukesha you can figure out when it's possible to plant ageratum by reviewing the USDA zone info.

Planting Calendar for Ageratum

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

It's probably not a good idea to plant ageratum until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant ageratum in Waukesha is April. However, you really should wait until May 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 really do well. If you are starting your ageratum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Waukesha the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Waukesha may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Waukesha there is a last frost after April 15 be ready to cover your ageratum if you have one of those late frosts.

USDA Zone Info for Waukesha

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 Waukesha

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