One of the first steps you take when you are making a decision about 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.

You will be able to determine when to plant columbine by checking out the USDA zone info for Rock Island.

Planting Calendar for Columbine

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

Since columbine are moderately cold tolerant you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant columbine 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 columbine and expect a good harvest is probably September. If you wait any later than that and your columbine may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your columbine indoors.

Last Frost Date

The average date of last frost is April 15 in Rock Island. You can expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Rock Island and it is different every year. Since half of the time in Rock Island there is a last frost after April 15 be ready to protect your columbine 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.