One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant anchusa in London should be determined by referring to the USDA zone info.

Planting Calendar for Anchusa

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

Anchusa do ok in a bit of cold which means that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant anchusa in London 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. Starting your anchusa indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in London. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for London is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in London you get surprised by a frost 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 London

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in London

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