My condolences....
My analysis and recommendation is for you to try to improve the
level of cordiality between the two of you.
This is the fundamental reason why such an occurance (falling
leaves) can cause a big problem.
So to solve this question, one needs to improve the relations
first.
First, I suggest that everytime you walk past her or meet her,
try to smile and nod to her.
Next, when the situation is ripe, try to say a few short
greetings and exchange some words.
Do this for some time to thaw the relations.
Now after the relations is relatively civil, next time when you
can find an appropriate opportunity, casually mention to her about
the leaves. If you can, do this delicately. First talk in general,
and then talk about the plants, say you are also plant lover, then
after that talk about the leaves, and mention that u somehow want
to ask her a favour to sweep the leaves to a bin, and not towards
your flat.
I hope you understand what I say.
I believe this is the only action you should take.
Dont try to escalate the matter. Dont escalate hostility. Doing
such thing will only bring a lose-lose outcome and is counter
productive. It is not in your interest.
If you find my suggestions to be difficult for you personally to
implement, try third parties, such as someone else in your family.
Think of someone who is suitable. Perhaps men talking to men will
be better. Approach your father to talk to the husband.
OK, good luck
can try this one.. i agree, shdnt make matters worse.. dont
complicate things.. all d best!