One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

In London you can determine when it's the best time to plant common hollyhock by reviewing the USDA zone info.

Planting Calendar for Common hollyhock

Frost tolerance for common hollyhock:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Common hollyhock can survive in some cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant common hollyhock 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 common hollyhock and expect a good harvest is probably September. You probably don't want to wait any later than that or else your common hollyhock may not have a chance to really do well. If you are starting your common hollyhock indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in London. It might get as low as -5°F during 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 there is a last frost after April 15 so make sure that you are ready to protect your common hollyhock 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.