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.

In Rock Island you can determine when to plant erysimum by referring to the USDA zone info.

Planting Calendar for Erysimum

Frost tolerance for erysimum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Erysimum are one of those plants that can tolerate a little bit of cold weather which means that you can start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant erysimum in Rock Island is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant erysimum and expect a good harvest is probably September. Any later than that and your erysimum may not have a chance to grow to maturity. If you are starting your erysimum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Rock Island the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Rock Island may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Rock Island you get surprised by a frost after April 15 so just be sure to be ready to cover your erysimum in the event of one of those late frosts.

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.