One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when it's possible to plant anchusa by referring to the USDA zone info for Topeka.

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 other plants that might not handle the cold.

The earliest that you can plant anchusa in Topeka 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 fully mature. You can get started a few weeks earlier by starting your anchusa indoors.

Last Frost Date

On average the last frost is on April 15 in Topeka. It might get as low as -10°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Topeka and it can change quite a bit from year to year. Half of the time in Topeka it frosts late in the year after April 15 so just be sure to be ready to cover your anchusa if you have a surprise late frost.

USDA Zone Info for Topeka

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Topeka

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