The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Rock Island should be used to estimate when you can plant mimulus.

Planting Calendar for Mimulus

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

Since mimulus are not cold tolerant it is necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant mimulus in Rock Island 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 fully mature. Starting your mimulus indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Rock Island. In the coldest months of winter you can expect an average low temperature of -15°F.

It's important to remember that USDA zone info for Rock Island is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Rock Island you get a frost after April 15 be ready to cover your mimulus in the event of a surprise late frost.

USDA Zone Info for Rock Island

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 Rock Island

You may be interested in your other planting guides for Rock Island.