Literally hunderds of white flowers on a tiny plant.
'Weisser Zwerg' means 'White Dwarf' but this has long been known as Iberis 'Little Gem' - and it really is a gem. There are a few Iberis, all claiming to be white and dwarf but, in my opinion, nothing matches 'Little Gem'. Even the tiniest plant, no more than a twig, can be crowded with buds which open into large heads of sparkling white flowers. I don't know how they do it - it almost defies logic! Even barely rooted cuttings manage it.
As well as these qualities, it is an easy-going garden plant that should do well in most good soils; it prefers sun but will take a bit of shade. It is small enough when young to be planted in a trough for a couple of years where it will be neat and bushy but it becomes looser with age. And it will last for years as it's very long-lived. About 20cm (8") high at most.
Listed as 'Little Gem' in a nursery catalogue as far back as 1903 - I told you it was long-lived!