might be a good idea. how tall is the stem? we usually don't use stakes unless the threat of rain is in the forecast. then we hustle to get all our plants tied up! one morning we woke up after a night of heavy mist and ALL of our super tall lilies (as well as lots of other plants), were bent over! it was heartbreaking. paint the stake dark green, it'll be virtually invisible once its tied to the lily!
hmm... sounds like some staking is needed. they shouldn't be bent over at such a short height. they should be plenty stiff to remain upright at only 14 inches. ive never really had that problem other than with tiny bulblettes, so I don't exactly know what advice to give. other than staking them up. and of course a god rain will weigh them down pretty good as well. what kind of conditions are they in?
I live in Virginia.... They are in full sun... I have them in a flower bed with 2 other lilies and daisies... I water them every evening if it doesn't rain
perhaps they are not planted deep enough. other than that, im at a loss. you didn't mention how long they have been in the ground. perhaps they are not mature enough to stand on their own yet...? maybe someone else has some better insight for you. sorry
Name: Elaine Sarasota, Fl The one constant in life is change
A picture would help us to see the problem. For sure you should stake them up if they keep falling over, but as Jason says, at that size they should stand up better.
Elaine
"Success is stumbling from failure to failure with no loss of enthusiasm." –Winston Churchill
other than that, im at a loss. you didn't mention how long they have been in the ground. perhaps they are not mature enough to stand on their own yet...? maybe someone else has some better insight for you. sorry 
