Mould Problem On My Hebedonna?

Hi Guys,

I'm an amateur hobby gardener and would like a bit of advice from anybody who may know what's happening with my Hebedonna. I purchased it from a reputable garden centre and planted it a few weeks ago. Since then I've noticed some of the leaves are looking a little on the ill side. I looked closely and noticed the back of these leaves looks almost mouldy. Can anybody tell me what and why this is happening, and more importantly, what can I do to bring this plant back to health?

Thank you in advance for your input!

Gary