One of the best tools that you have as gardeners to help us determine 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.

You should be able to figure out when it's the best time to plant ageratum by reviewing the USDA zone info for Northbrook.

Planting Calendar for Ageratum

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

Since ageratum require warm weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant ageratum in Northbrook 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. If you wait any later than that and your ageratum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your ageratum indoors.

Last Frost Date

In Northbrook the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

It's important to remember that USDA zone info for Northbrook is just an average and the actual date of last frost is different every year. Half of the time in Northbrook it frosts late in the year after April 15 so make sure that you are ready to cover your ageratum if you have one of those late frosts.

USDA Zone Info for Northbrook

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 Northbrook

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