Question
I have a shamrock plant that all of the leaves have brown spots and the outside edges are brown.

Answer
Hi

Sorry for the delay--computer crash on my end.  The plant may have either a fungal rust which would be obvious orange color on the underside of the leaves.  The other possibility is spider mites.  They are small mites almost not visible, but may produce a little white webbing that may be visible.  If you suspect the mites, I would treat the plant with Bayer Advanced Tree and Shrub Insecticide.  This product is mixed with water and poured on the soil around the base of the plant.  It is taken up systemically and will kill the bugs within a week or so.  It also provides protection from reinfestation for up to a year.  This should fix the problem.  Good Luck.