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.

By using the USDA zone info for Colby you will be able to determine when it's a good idea to plant anchusa.

Planting Calendar for Anchusa

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

Anchusa are very cold tolerant which means that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant anchusa in Colby 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. If you wait any later than that and your anchusa may not have a chance to really do well. Starting your anchusa indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Colby. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Colby may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Colby last frost occurs after April 15 be ready to protect your anchusa if you have one of those late frosts.

USDA Zone Info for Colby

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 Colby

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