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

In River Rouge you can estimate when it's the best time to plant mimulus by referring to the USDA zone info.

Planting Calendar for Mimulus

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

It's probably not a good idea to plant mimulus until after the last frost because they require warm weather.

The earliest that you can plant mimulus in River Rouge 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 mimulus and expect a good harvest is probably August. Any later than that and your mimulus may not have a chance to really do well. If you are starting your mimulus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in River Rouge. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for River Rouge 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 River Rouge last frost occurs after April 15 be ready to cover your mimulus in the event of a surprise late frost.

USDA Zone Info for River Rouge

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in River Rouge

You may be interested in your other planting guides for River Rouge.