One of the first steps you take when you are getting a good idea 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.

A way of determining when to plant iberis is to use the USDA zone info for London.

Planting Calendar for Iberis

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

Iberis are moderately cold tolerant which tells us that you can start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant iberis 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 iberis and expect a good harvest is probably September. If you wait any later than that and your iberis may not have a chance to grow to maturity. Starting your iberis indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for London and it is different every year. Since half of the time in London you get a frost after April 15 be ready to protect your iberis 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.