One of the first steps you take when you are figuring out 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.

It's possible to estimate when you can plant anchusa by using the USDA zone info for Helena.

Planting Calendar for Anchusa

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

You can plant anchusa a lot earlier in the year because they do well in cold.

The earliest that you can plant anchusa in Helena 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. You probably don't want to wait any later than that or else 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 little bit earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Helena and it will vary from year to year. Half of the time in Helena there is a last frost after March 15 so always be ready to protect your anchusa in the event of a surprise late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Helena

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