One of the first steps you take when you are getting a good idea 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.

The best time to plant ageratum in Pierre should be figured out by checking out the USDA zone info.

Planting Calendar for Ageratum

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

Ageratum do not do well in cold weather which means that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant ageratum in Pierre 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. You probably don't want to wait any later than that or else your ageratum may not have a chance to fully mature. 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

On average all chance of frost has passed is on May 15 in Pierre. It might get as low as -25°F during the coldest months of winter.

Remember that USDA zone info for Pierre is an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Pierre last frost occurs after May 15 be ready to cover your ageratum in the event of a surprise late frost.

USDA Zone Info for Pierre

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 Pierre

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