When can I plant Anchusa in Zone 4a

One of the first steps we take when we are estimating our gardening schedule is find our USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for our area.

By reviewing the USDA zone info for Zone 4a it's a good idea to determine when it's a good idea to plant anchusa.


Planting Calendar for Anchusa

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

Anchusa are one of those plants that can tolerate quite a bit of cold weather which tells us that you can start planting them much earlier than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant anchusa
Possibly ok, but a risky time to plant anchusa
Probably not a good time to plant anchusa

The earliest that you can plant anchusa in Zone 4a 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 anchusa and expect a good harvest is probably August. 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 few weeks earlier.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Zone 4a is just an average our actual date of last frost is different every year. Half of the time in Zone 4a we get surprised by a frost after May 15 so just be sure to be ready to protect your anchusa in the event of a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)May 15
Average Date of First Frost (fall)September 15
Lowest Expected Low-30°F
Highest Expected Low-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in our other planting guides for Zone 4a.