Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant hollyhocks in London should be estimated by using the USDA zone info.

Planting Calendar for Hollyhocks

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

Hollyhocks do well in a little bit of cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant hollyhocks 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 hollyhocks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your hollyhocks indoors.

Last Frost Date

In London the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that USDA zone info for London is just an average and the actual date of last frost is different every year. Since half of the time in London there is a last frost after April 15 be ready to cover your hollyhocks in the event of 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.