One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. 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 tarragon in Rock Island should be estimated by using the USDA zone info.

Planting Calendar for Tarragon

Frost tolerance for tarragon:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since tarragon do ok in moderate cold you can plant them just a tiny bit earlier in the year than more sensitive plants.

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

The last month that you can plant tarragon and expect a good harvest is probably August. Any later than that and your tarragon may not have a chance to fully mature. If you are starting your tarragon indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Rock Island is just an average and the actual date of last frost is different every year. Half of the time in Rock Island you get surprised by a frost after April 15 so be sure to be ready to cover your tarragon if you have 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.