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

The best time to plant ageratum in Stillwater can be determined by using the USDA zone info.

Planting Calendar for Ageratum

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

Ageratum do not do well in cold weather which tells us that you have to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant ageratum in Stillwater 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 grow to maturity. You can get started a couple of weeks earlier by starting your ageratum indoors.

Last Frost Date

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

Remember that USDA zone info for Stillwater may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Stillwater last frost occurs after May 15 be ready to protect your ageratum if you have a surprise late frost.

USDA Zone Info for Stillwater

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 Stillwater

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