One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Douglas it's possible to figure out when you can plant ageratum.

Planting Calendar for Ageratum

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

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 Douglas 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. If you wait any later than that and your ageratum may not have a chance to fully mature. Starting your ageratum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Douglas the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Douglas is an average and the actual date of last frost changes from year to year. Half of the time in Douglas you get a frost after May 15 so make sure that you are ready to protect your ageratum in the event of a surprise late frost.

USDA Zone Info for Douglas

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 Douglas

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