This has been happening in my game recently. I use the crocus scented flower trick, but when they die all bets are off. My garden is outside in a covered two-story tall, (for the height of the trees), greenhouse with no sides. They're either irritated or enraged all the time no matter whether it's spring, summer, or fall.
I think there's one that keeps plants around longer but I don't remember which one.
I got tired of my sim getting stung all the time, (Lucky there's no "Death by Bee Sting" or all of my sims would be orphans-Don't get any ideas now), and had him build a sim bot (I have University) and now the only one that gardens, cooks, and tends to the youngsters is the bot. The baby's mom is a student and works so she's always doing homework and they needed help.
As for the music helping them, I'm not sure about that one.
I'm going to try putting a thermostat on an outside wall Then I'll try lowering the outer fencing and see if either of those make a difference. . If not, then I'll have to do without the bees yet again.
