Tiny ageratum

I purchased seeds of Ageratum Blue Horizon from Chiltern Seeds and sowed them in March this year. They germinated just fine and so I planted the seedlings out in May. I was expecting the plants to be around 1½ - 2½ ft tall but, as you can see from the photo below, they are in fact only around 4 inches tall.



I sent an email to Chiltern Seeds who profess themselves mystified. They have checked their packaging and say the seeds were correctly packed, so can't offer an explanation (although they will send me some more with their compliments).

Maybe it's just due to the appalling summer weather, i.e. lots of rain and no sun. Any ideas?

 

I love it Tiarella!! I have a postage size patio garden with a border at the back and on one side only. Things like this are the ones I have to look for. And it's blue - one of my favourite colours.
Would look nice in a hanging basket too,

 

Tiarella, was the height that you've stated on the packaging. I've got Ageratum in my garden and they are no taller than about nine inches. As far as I know this is the normal height.