One of the first steps you take when you are making a decision about 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 a good idea to estimate when you can plant helianthemum by using the USDA zone info for London.

Planting Calendar for Helianthemum

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

Helianthemum are moderately cold tolerant which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

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

Last Frost Date

In London the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for London is not always accurate and the actual date of last frost is different every year. Half of the time in London you get a frost after April 15 so just be sure to be ready to cover your helianthemum if you have a surprise late frost.

USDA Zone Info for London

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in London

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