How can I stop Abutilon 'Kentish Belle' from getting leggy?

Hi everyone

I have one of these, planted about two years ago. It's still a bit moribund at the moment, about 2' high, but everything's like that in my garden, and I have no doubt that this year or next year it'll start to take off.

My problem is that I can see it's already starting to get leggy: long branches with a few leaves and flower buds on the top. Is there anything I can do to prevent this legginess?

Planted against a wall in good neutral soil in the SE (London), a very sheltered and sunny spot.

 

What direction does the wall face?

 

The wall faces South.

 

Ok - you've done all you can.
They are slightly leggy plants. I grew it behind other shrubs and tied it into the fence at my last house.
They become more vigorous over time.