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

A way of getting a good idea when it's the best time to plant anchusa is to look at the USDA zone info for Naperville.

Planting Calendar for Anchusa

Frost tolerance for anchusa:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since anchusa are very cold tolerant you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant anchusa in Naperville 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 anchusa and expect a good harvest is probably September. Any later than that and your anchusa may not have a chance to really do well. If you are starting your anchusa 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 Naperville. In the coldest months of winter you should expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Naperville may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Naperville there is a last frost after April 15 be ready to protect your anchusa in the event of one of those late frosts.

USDA Zone Info for Naperville

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 Naperville

You may be interested in your other planting guides for Naperville.