Try a motion sensing sprinkler. They are about $50, but can be pretty effective without being harmful to the cats.

Where I live, cats must be "in control" of their owners. The local animal shelter keeps cat traps for just this purpose. Eventually my neighbor got the hint (fines at the shelter escalate rapidly).

I feel your pain, and best of luck.

I have a problem with a neighbors small dogs digging up my front garden. I just installed one of those $40 scarecrow motion detected sprinklers off amazon. So far no more digging has occured, but it's only been a week so far.

I think the motion sensors are a great idea. What about sensor lights for nighttime? The kind that turn on strong light whenever a specific area is approached. I'm sure the cats won't like that and may get the hint.

Are other neighbors complaining? You may be able to file a nuisance claim with your city. It's the same basic idea that prevents your neighbor from running a lawn mower at 5 am. These cats are disrupting your peaceful enjoyment of your own home. If you'd rather avoid the legal route, you can put out humane cat traps on your property and just call animal control whenever you catch one. Admittedly, that's a pretty bold move, but they are on your property. You could also collect all the cat poop and return it to their owner...

You could try some sort of electric cat repellent (provided you don't own cats that would be bothered by it)- Google "Cat Stop". Also, cats hate citrus so you could spread some sort of citrus oil around your property line, or plant some citrus trees (climate permitted). Good luck!

Do you ever notice people visiting her? Hoarders are very often lonely people who have alienated family members and friends either because of their hoarding tendancies or because they've had longstanding mental illness that led to these tendancies. If you see family members or friends visiting, there's hope that maybe you can speak to them and see whether there is anything they can do about the cats.

I understand the township can't do anything except fine, ticket, etc. and what she's doing isn't really criminal, but how come the family has complained but has not been able to do anything themselves? You should try to speak to the family. Barring that, your best tactic is most likely to build a fence (if you can) and because you don't intend to move, you don't have to worry about property values for when the news cameras are filming outside your home because the hoarder lady has had all of her cats taken away and the police are hauling out gigantic piles of rotting trash (I'm being a tiny bit hyperbolic). :)

I have never heard of a motion detector sprinkler, that is a brillant idea! Where I live if the cat is not collared, spayed, micro-chiped, or otherwise cared for (simply feeding does not count) then they are considered feral and can be trapped and removed by animal control.

Are there any laws about the number of domesticated animals you can legally own? I thought most towns had restrictions. I think the motion sensor sprinkler could would be great. Maybe after a while they would even learn to just avoid your yard and you could remove the sprinklers.

Have you talked to the local animal rescue groups as well as the town? They may have different definitions of why they're willing to call abuse. Hoarder raids can also be very expensive, which is why the town may be tempted to turn a blind eye rigt now, but an animal rescue group may care enough to do something.

One problem is that hoarders often promptly go out and find more animals when theirs are taken away. :(

Motion sprinklers sounds like a good idea, and if you don't have pets of your own, you could try biological deterrents like the anti-racoon pepper sprays on the edge of the property.

If the cats have sprayed your porch, you'll want to use an enzyme cleaner to discourage repeat visits. And you may want to temporarily give up any mint plants you have or move them indoors, as some varieties smell like catnip.

... Heck, maybe giving the neighbor some catnip plants for HER yard might help.

Ugh, that sucks. Since it sounds like your township has no problem with 10 pets in a single family home (!! - I think here the limit is 4), it sounds like your only option is mitigation. Is your yard fenced? If so, and if you're willing to spend a little $$, there are systems that will attach to the top of the fence to keep cats out - they are like a springy nylon that cats won't jump on. Otherwise, you could try motion activated sprinklers or Shake-Away and other predator urine products. For the flowerbeds, I've also heard that cats HATE walking on chicken wire, and that if you lay that down with holes cut for your plants, they'll leave it alone, though I haven't tried this.

You could also trap the cats in your yard and take them to the shelter (I would have no problem claiming a cat constantly in my yard with no collar was a stray), but since she's a hoarder she'd probably just get more. Since she's not responsive, any chance talking to her family members would help? Maybe they could talk her down to just one or two cats, and make sure they're fixed.

CITRUS!! Cat's hate the smell of citrus - cut open a few oranges, grapefruit and leave them on your porch, squeeze them around your lawn - see if that helps!

I went through this a few years ago, the cats even peed through my open windows onto my bed (once) and sofa (twice), and clawed through the screen in my back room to get in and bring fleas! Eventually, the hoarding, garbage burning (yep, in the yard!), animal loving neighbours moved. In the meantime I had some success with a combination of (unattractive) tactics. It was important to me that the cats not be harmed.

- Pigeon spikes on the window sills and anywhere the cats wanted to hang out (porch, steps, planter edges). If you live in a city, you can get these at most larger hardware stores. A coil of chicken wire can work too, just something to make it awkward/uncomfortable for them to lounge on.

- Chopsticks, bamboo skewers or similar sticking up around plants in planter boxes or garden beds can help keep the cats from eating, digging and defecating in the area.

- Mulch your garden/planters with something rocky. It isn't nice to dig or lounge in. Lava rock is good, pea gravel is bad (too small and litter like).

- There are several types of odour based repellents that you can find in pet, hunting, and Home Depot type stores, or make your own (Google a recipe). You'll need to re-apply these frequently so it can get pricey if you need to cover a large area.I used them on the inside of my windowsills when the windows were open.

- In my area, we're allowed to humane-trap animals that are nuisances and take them to the SPCA. Is this an option for you? Sometimes you can borrow or rent live-traps from the SPCA. If not, try craigslist for used ones or hardware stores for new ones.

Good luck.

Are you sure these are domesticated cats? Are they just feral cats that basically just stay nearby because they're used to being fed by this woman? If the township wasn't paying too much attention and they are feral cats, you should look at the laws that govern the township (usually state, I think. We don't have townships so I don't know) and see whether there is any legal definition of feral vs. domestic.

I would reach out to the local animal shelters. My guess is that these cats aren't vaccinated and if they're howling outside your windows, they probably aren't neutered/spayed, which presents an even larger concern for your area (those 10 cats could turn into 100 cats in your garden). Many shelters have trap/neuter/release programs - often when the shelters discover that trapped cats are friendly, they will try to adopt the cats out to good owners, rather than releasing them back into the neighborhood they were found. It isn't the cats' fault they have a crappy owner. Consider solutions that will solve your problem AND improve these cats' quality of life. Act quickly though - kitten season will be starting very soon!

Defintely call an animal rescue group. If they determine they are being mistreated they will be oughta there! You still might consider a fence because, yes she will find/attract more cats and it will conceal her clutter. I feel your pain. Last summer I planted $300 in evergreens to cover up my neighbors junk. Every morning I look out my living room window at them and whisper "Grow!'

Motion-activated sprinklers (cats are smart enough to predict when a regularly set sprinkler goes off - I know only because I tried it!), spray vinegar where you don't want them to settle, use citrus peels and citrus spray (peels and liquids need to be refreshed every other day or so), those are your most animal-friendly solutions. The cats aren't feral if they let you see them, you won't see true feral cats, I'm active in a cat rescue group and there's a big difference between the behavior of stray cats/outdoor cats and feral cats. Indoors, for you, a white sound machine will help you sleep at night and will help mute the startling sound of a cat vocalizing outside your window - it won't drown it out completely but it's enough to take the edge off and not interrupt your sleep - I used it when a neighbor's cat was allowed to roam at night and would come tempt my cats through the window (they were renters - thank Heaven they moved!). I also, occasionally, would open the window and spritz that cat with a small water gun filled with pickle juice... that helped discourage him from his nighttime activities... it wasn't exactly animal-polite but by that point I was so sleep-deprived I just wanted him gone (he killed two of my cats and I ended up having to keep the other 2 as indoor only for the remainder of their lives). That's the only cat I've ever truly disliked...

@RUCY - maybe not feral, but domesticated cats that are just strays? Either way, a problem for the neighbors if they're allowed to roam free and disrupt other people's property.

Depending on how fa you want to go their are some extreme things you can do. I agree that the motion-detecting systems are a good, but I will suggest a few more idea. Electric Pet Fences will prevent animals like those cats and even other animal from entering your perimeter. Plant Lemon Balm its a natural cat repellent used to ward off tigers in India. Plant Cat Nip in an area away from where you want them to go. Citrus peels in the garden. I've even heard someone put a dried snake skin in there flower bed and it kept cats out. This is gross, but some people use the urine from other animals on their perimeters to keep out other animals. Ground black pepper around your plants. Mint. And there are cat repellents you can buy, but I'd don't know about those. And for the most extreme. Adopt a dog from your local shelter. That will keep them away.

I'm with Famous Amos. Basically, you want your yard to be unattractive to cats, so no nice fluffy surfaces to use as a litter box, lava rock is a great idea. Plastic forks work great to stick in planters (one of my neighbors did that) although they look a little silly.
Also get rid of any plants they might like and your bird feeder if you have one.
My very first thought was actually "get a dog", the bigger the better. But that might not be an option for you. I'm not suggesting leaving the dog outside all the time, just having him run around in the yard a few times a day will improve the situation. Maybe a friend with a dog can visit?
I would not suggest trapping the cats yourself. You don't want to risk getting scratched or bit.
I bet the cats aren't vaccinated. Can you complain to the township about the health hazard of having a bunch of cats in your yard? Especially if there are kids in the area.
I would guess that the only way the cats will go away is to take their food away, all neighbors (including the hoarder) would have to do this though, which seems unlikely.
I would reach out to a rescue group - simply because they might have more ideas and they know your township's laws too.

I'm surprised the city you live in hasn't involved the human society. I lived in an area where dogs would bark ALL DAY until their owners came home. It took a while, but eventually, they gave the dogs up because of all the notices left by the police and the Human Society.
I'm also surprised that they haven't condemed her property. Tat usually is the last step, but it does happen. If she is hoarding, can you imagine what it must look like inside?
There is a program on TV called HOARDERS. This may be a long shot, but try googling them and see if they can answer/help you out with this. I feel for you, I really do.

I'm with the trap them and take them to the Animal Shelter. I would warn the neighbor that if they don't move the cats indoors that that is what you're planning on doing. If she's concerned about her cats at all and takes your threat seriously she will move them inside.

You describe the problem as "constantly on our porch, in our backyard, in the flowerbeds, screeching outside our windows at night, and so on."

But you don't say whether they are causing damage? Cats on the porch or in the yard that aren't causing damage aren't much different than say, birds, rabbits, and mice. They're just larger and tend not to run away when humans come close. If you don't like cats, then it's an annoyance--but what exactly is the problem? Defining the problem is likely to lead you to the right solution. Do you prefer dogs? We have two, and very few neighborhood cats risk our backyard.

Night time yowling suggests a spay/neuter problem and a growing colony. As others have said, animal rescue is a good start. If there are no kittens, however, then it's not a spay/neuter issue at all. It could just be a territory conflict with any neighborhood cat. Is it just one cat yowling? If you can identify the individual(s), perhaps it's a lone Tom, or a pair vying for space?

We also have two cats and leave the garage cracked for in/out access vis a vie the laundry room. For whatever reason, our nieghbor's cat frequently wants to get into the garage and use our cats' litter box, and that always causes territorial yowling. If we close the garage at night, there's no yowling. My point is that we understand why we've got the issue and we know how to manage it. It doesn't sound like you've actually put a lot of time into parsing out what the actual problems are, vs annoyances, vs irritating eyesores. Granted, it's not "your" problem per se, but since it's causing enough stress in your life, it's become yours... I think if you want to resolve it, you'll have to own it a little more and get to the root of the problems that can be addressed, vs. unwelcome company that you might learn to live with if the problems went away.

@FABULOUSNFRESH - Good ideas, but hoarders are rarely rational people. She's "taking care of" her cats even though she isn't. They might not be abused, but they certainly aren't being controlled. Leaving cats outside all the time is letting them get hit by cars, attacked by other animals, etc. Explaining to the neighbor or threatening to report her might not work since she probably doesn't think she's doing anything wrong.

All those cats probably help keep the rat population down, something to consider when there's a hoarder.

Look into an electronic noise deterrent. They can be triggered by the animal or left on all the time and would hopefully keep them off your property. That is unless you have animals of your own, which in that case you could turn it off when they are outdoors.
Cats can devastate an ecosystem (even a small one like a neighborhood) and they procreate very quickly. If they are not fixed then you should talk to a shelter that would be willing to pick up and re-release. I doubt the hoarder would notice and then you could at least know that the animals won't multiply.
Make sure that you aren't not in anyway inadvertently attracting them to your home by leaving water or food out. Make sure that your trash and the like is put away and covered tightly. Also make sure that your house (if you have a crawlspace or the like) is closed off to their access. You do not want to find that they have been living there and only eating at the hoarder's home. Cats can do a lot of damage to a crawlspace of a home if allowed to climb in by accident.
I love cats and growing up we had a number. So this is not coming from a person who hates cats. You can smell where they have been, the ammonia smell is horrible. In my area the mall became a local dump for cats because people knew someone was feeding them, they grew out of control. You don't want this to be the issue with this person next door. Good luck!

Sprinkle coffee grounds around your porch, in your flower beds, or anywhere else they hang out. Cats (racoons, squirrels, skunks) hate the smell of coffee and will usually leave the area alone. As a plus, its also great for most plants!

Also on a different note, as someone who has moved from the country to a neighborhood...I have been surprised by the mount of cats that are "let out for the night" People if you aren't willing to let your dog "out for the night" why do you let your cats out? I understand that they are independent creatures but in the end they often end up in the streets, on neighbor's porches, taken, lost, or killed by cars or other animals. Why, if you love your cats, would you let them out of the protection of your home to possibly get hit by cars?
it isn't like living on 10 acres of land where a cat runs between the house and the shed or barn...

a dog?

LOL, MichelleM9, I was temped to post "get a greyhound".

To the OP - I feel for you. It drives me nuts when a single cat from the house across the street gets into my back yard. The reason - my greyhounds would chase it and if they caught it, it would not be pretty. As much as I dislike the cat, I don't want it to be harmed and the potential for my own dogs being injured is even greater (those feline claws, I would not them to get anywhere my darlings' eyes).

Can you talk to your local Humane Society to check what options you have? We have a limit of 3 dogs per household where I live (sorry, don't know if it's pets in general or dogs specifically) but Humane Society does not care how many a person has as long as all have their license and as long as nobody complains. If somebody complains, they would investigate (it happened to me - somebody who never met me and doesn't even live in my city complained to our HS that I have 5 grehounds [I did have 5 at that time]. He did it out of spite because we bitt3erly disagreed on some rather hot issue on a greyhound mailing list). One day, I returned home from work to find a tag from the HS on my door. Of course I ran there the next day wanting to know what the complaint was about (they don't bark, are walked on leashes, I pick up poop, etc.). of course they promptly got rid of the whole "complaint" when it dawned on me where the wind was blowing from.
Good luck dealing with this.
Motion sprinklers are a very good idea, I would try those and the citrus fruit.
I believe that people sometimes use predator urine to deter some wildlife but I would prefer to sprinkle orange juice around the house instead of coyote urine (besides, the coyote urine gets a bit pricey).

All great suggestions so far. Here's a website that gives a few more http://www.cat-repellant.info/html/diy-cat-deterrents.htm

Someone mentioned other animal urine and this actually works. At your local garden store you should be able to find something called "Coyote Urine". It's not actually from live Coyotes, it's a products thats been made that replicates the scent of Coyote urine. It helps to keep squirrels, deer and rabbits out of the garden so I would assume it would work for cats as well.

Good luck

A friend's parents had a similar issue. They installed a device that gave out a super high pitched sound that almost no one can hear, but cats hate. That worked for them.

There are excellent long term suggestions posted here. While folks determine costs and make arrangements etc. my "quick fix" suggestion may be useful. This is where foil wrap comes in. It is not a long term solution but once put over flower garden areas and porch surfaces the cats will NOT walk in those areas. The very best suggestions in my opinion were the motion detecting water spray and the chicken wire under the soil. I have two siamese cats and use foil myself in a few areas outside.

Remember that whatever you do, approach this with love (I know you will, you understand they have an illness and there is no malicious intent on her part). Sometimes we forget the spiritual remedies to Life's problems.
Hopefully they're all neutered/spayed and she hasn't been adding more cats to the clutter!

If you involve an animal shelter please make sure it's a "no kill" shelter. Some of them still kill cats if they haven't been adopted out after so much time.

I sure wouldn't go out and spend a lot of money to re-landscape your yard or install electric fences and such! This is HER problem, not yours. I very much doubt these are her cared-for PETS. They are outdoors, probably not getting vaccinations regularly (do you see her leaving the house often with a cat carrier to go to the vet? if not, with 10 cats you can bet she NEVER goes to the vet) and quite possibly not neutered. Unless you have witnessed them coming up to you and being friendly, you can assume they are feral or close enough to feral that adoption is not ever going to be an option.

Some cities will do spay/neuter release, but to do that the person who brings them in generally has to pay $50-$100 for the neuter PLUS is required to pay for vaccinations (which totally escapes me, because what the hell good is it to do it once???). Cat lovers need to cover their eyes now: unless you want to pay through the nose for this woman's animals, and KEEP doing so, because as long as she leaves food out more will come, you have to trap them and take them to the shelter. Better yet, call animal control and explain the situation and see if they will come set up the traps for you, so you can close your eyes and pretend it's not happening. A "no-kill" shelter will NOT take feral cats - they are dangerous (to people trying to handle them, because cat bites are cess pools for infection) and unadoptable.

What determines the ownership of a cat? If they are in YOUR yard, it seems to me they are no longer HERS. I would simply catch as many as possible, as often as possible, and take them to the local shelter. Period. She'll either keep them out of your yard, or be prepared to say goodbye. I am not a cat hater (I own one) but you should not have to sprinkle coffee grounds, animal urine or anything else in your own yard.

P.S. Hate me if you want, but I have no problem with stray cats being HUMANELY put to sleep. It's much better than being hit by a car, attacked by wild animals, starving, or living with disease and infestation.

Look for the nearest "Alley Cat" non-profit, who usually have volunteers to do a trap, spay, and release program. They check for diseases like FIV, FLV, distemper, etc., and if the cats have any, they are euthanized. Otherwise, they are vaccinated, spayed, and returned, but at lease then don't keep reproducing.

Not okay....for you! This person, whatEVER her own problems are, does NOT mean that they are to become YOUR problems...It's called living with the social norms of ANY neighborhood and she is unable to do that nor care to..very obviously..she is in the wrong totally, not you. You need to be powerful in your demanding that this situation be cleaned up as it has affected your well being and enjoyment of your home and life. There has to be accountability legally as she is unable to understand that her lifestyle has grossly affected yours and probably others. Take pictures, tape the sounds, and call THE NEWS STATION...someone HAS to force the issue for you and the neighbor and her living conditions....don't let it keep you, who lives as a thoughtful and civilized person from living in peace. She needs help and doesn't recognize anything as being NOT OKAY>> good luck..I love cats..but not the situation that has allowed them to seemingly run ferral and most likely sick as well..no pussyfooting around anymore...

feral..(with all my ranting..)

We built a raised bed for veggies the other year and it was clear from the start our many neighborhood kitties thought they had just been given a new, deluxe litterbox. One inexpensive pack of bamboo skewers solved the problem. They are sticking out all around the perimeters, sharp side up, and every few inches inside while veggies are still small- until lettuce, etc, gets big enough that they won't try to walk on it. No cats actually harm themselves- they are cautious creatures- they see that it would be uncomfortable to pick their way through the sharp spikes and they just move on to easier pastures.

PS- We still haven't figured out how to keep the many feral cats in the neighborhood from passing through the rest of our yard. It's a kitty highway and drives our two indoor cats crazy. We tried various predator urines and it didn't work, they just wash away and I didn't care to religiously maintain them. We hope to plant flowers and bushes that are natural repellants, at least near the basement windows. Good luck.

I would definitely involve the authorities all you can. Take photos, (document, document, document ), and send your complaints to the city council, adult protection, animal protection, the city complaint center, EVERYWHERE and keep calling until you get a response. It took me years but I finally got a "problem house" cleaned up when kept at it.

Hoarders will not change unless they are up against a wall, and even then it is difficult. Those cats may have serious health issues that can spread to others if not addressed. Good luck.

Put chilli powder on your window sills and porch.

The cats will learn pretty quickly where not to walk.

Good thing this isn't my neighbor! I don't have room for any more litter boxes. As the caretaker for 6 furballs, I would recommend catching the cats and taking them to a shelter if your animal control/city/township doesn't trap stray animals. I, too, would rather see them euthanized than hit by a car or starved. Please see if there are any cat rescue places in your area that would/could assist you with resolving your cat problem. As another commenter said: it's not the cats' fault they have a crappy owner. PS my cats are all strictly indoor cats. They never get outdoors because I know it's not safe and I rescued them to save them. The reason I don't have more is: no room for extra litter boxes and in my county, you have to have a cattery license if you have over six cats, even if you're not breeding! I also support the T/N/R units.

Yeah, I'd catch them and drop them off at the pound. I have had outdoor cats before and generally have no problem with it (and love to hear sanctimonious a-holes tell me otherwise), but these don't sound like outdoor cats so much as feral cats. Being a responsible pet owner is about more than just not starving or abusing animals. Having that many pets, when she clearly is not adequately taking responsibility for any of them, is absurd. Hopefully they can find homes that will actually step up and deal with them instead of letting them run wild.

Take them to the shelter. period end of story. Anyone with 10 cats isn't taking care of them properly. Call the city about the the filth over and over again until it's fixed. The filth, the critters it attracts and cats are not something you should learn to live with nor should you spend your own money adapting to her.

I too have a problem with cat's pooing in my garden, I dislike cats personally and really hate having to clean up their poo! The chicken wire in the soil sounds like a great idea, thanks AT.

HOLLER I guess I am that "sanctimonious a-hole" telling you otherwise. I only made my previous comment as a question on why people in suburban or urban areas have outdoor cats because in my neighborhood I often see more cats that have been hit by cars than nearly any other animal on the road. It is sad that when I am walking through the neighborhood with my dog, how few people seem to car that their cats are out in the middle of the busy streets. Sure I have had outdoor cats. I also grew up out in the country and far from the road but the average outdoor cat will still roam up to 5 acres for its territory. Their life spans are also much smaller compared to indoor cats so...I guess I am just wondering why keep a cat if you are only ever going to have it outdoors unless you live on a farm and are using it as a barn cat to keep mice away?

My neighbor's cat does the same thing. We tried all the natural remedies. Those didn't work. We ended up putting moth balls in a plastic jar with holes poked in the top into our flower beds. The cat leaves us pretty well alone now.

@SGGVT04 I wasn't really specifically talking about you, I just seem to have heard more than my share of people lately declaiming the evils of letting cats outdoors, and it gets tiring. I had two cats growing up in the suburbs, both eventually eaten by coyotes. One definitely should have been an indoor cat, since he clearly was not cut out for it and got gobbled up when he was only a couple years old. If I had that cat today, I definitely would not have him go outdoors more than just the occasional excursion. The other had 13 great years of keeping our garden safe from voles and bunnies by day and coming in for some scratches and a nap on the heating vent at night, before getting reabsorbed into the food chain. For the cat he was, I honestly think it would have been cruel to keep him cooped up all day, since we weren't living just off a highway or some other place that would have posed a legitimate threat to his existence. Some cats are savvy enough to make a living outdoors and can manage the dangers that come with it, and some are just naturally housecats who will settle in for a nap on the warm asphalt if given the chance, and probably shouldn't be let out too often. I am just tired of people who think that they are the big expert unilaterally deciding, without having any idea what they are talking about, that people are unfit pet owners for letting their pets outside when in all probability, those people are probably just familiar with their pet and giving it a happy, healthy life. People who make those kinds of judgements are the sanctimonious a-holes I was talking about, but I really don't know if that was what you were saying or not, so it wasn't really directed at you so much as in general.

Cat traps. Check craigslist. Take them to the local shelter. Repeated trips will definitely drive the point home as a previous poster said. Going on a road trip? You could take the trapped cat to the shelter at your destination. I'm sorry your neighbor isn't doing right by these animals. Keep pestering the humane society.

I like cats. If my mother wouldn’t be allergic I would buy myself one or two.
But I hate the cats of my neighbor. Of course those animals are not responsible for her strange behavior. And of course she is ill. She is a hoarder. She was since she was a child, as far I heard from others, that know her, from childhood on. She has family in the village, I think it ´s their term to do something (psychological help etc.).
That woman is rich (daddy pays…) and in the past she had different types of animals in her house. Once it was pigs. A lot of pigs. Not one or two, must have been a dozen. Direct neighbors told us, that it was so smelly, they couldn´t use their porch, they could not even open their windows.
I´ve heard a lot of stories about her and her animal hoarding.
She had once over 100 (!) sheep and other farm animals on meadows around our village and every time veterinary department came, they moved the animals in an overnight rescue campaign. Once or twice the animals were not gone and most of them were so ill, that they needed to be euthanized on the meadow. The veterinarian didn´t wanted to move them, they were suffering from foot-and-mouth disease.
Right now, they have “only” more or less 15 cats and all the other neighbors are frustrated. Nobody can leave something textile on his porch. The cats are peeing on those things and shredding them. I throw away my cushions of my garden furniture. Now I need to buy new ones. Those cats are although peeing on some house walls, and the pooh is everywhere. Everybody has lost fun in having a kitchen garden. Last year there were in one row of salad more than 10 pooh heaps some were buried and when I removed the weeds I digged them out. That was so disgusting, I didn´t wanted to eat my vegetables. 
We tried black pepper, chili powder and we have a motion detected light at the house. We although tried some sprays from the garden center that are for keeping cats away, but all this did not function or not long enough. The cats are coming 24 hours a day, every day. Sitting on the window, reading, I can follow them shiting (sorry, bad word) in my kitchen garden. Once I counted 14 at a time, all in your garden, all were walking straight to my kitchen garden to pooh. I´m not sure which ones belong to the hoarder, but I don´t care. They are in my garden. It´s a 1000m² garden. I can´t chance the complete fence.
Neighbors once catched them and brought them to an animal shelter or just abandoned them a few miles away from our village. But she, the hoarder knows all of her cats and walks around then, searching for them and she goes on other peoples ground, without asking. But people are afraid of her. She once tried to kill the veterinarian, who said, that those sheep and goats have to die.
I wouldn´t kill an animal. Some people say, if those cats are in there kitchen garden, they will throw stones or other things at the cats. Someone asked me, why we are not using poisonous meat traps. But why killing those animals, some of them are really beautiful animals and I´m sure, with another owner, those animals would have a good life.
And all those things with chicken wire, plastic forks, I can´t do this, I´ve little kids. It would be insecure for them too.
The local authority told us, that, as far, as those cats are not ill and bad treaded, they can´t do anything. But now all neighbors know, that its soon time for the kittens to be born and we all fear this moment. Those cats are not sterilized and of course they have no vaccinations. Maybe they are connecting for a class action suit. I will only plant peas in my garden this year.
Last year I planted some marigolds / tagetes, I think, that helped a little.

yikes, you're a kinder person than me. If all of that had happened and taking them to the shelter etc. still hadn't done anything, I'd definitely start researching the most humane ways of exterminating the cats myself. Good luck!

If there's one thing I've learned from watching Hoarders, it's this: where there are live cats, there are dead cats too.

If there's that many cats spilling over into your yard, then there's probably even more cats in her house. Unvaccinated, unneutered, uncared for. I don't think citrus or a sprinkler is gonna be anything more than putting a tiny bandaid on a giant wound.

And the cat problem is likely only the first wave of suck for you as her neighbor. You could be dealing with overwhelming odors and roach infestations that cross from her property to yours at the very least in the near future. The cats are probably keeping vermin at bay, but if the hoard's filling her backyard that's another issue you'll be dealing with and could end up in your house. Mice/rats/etc can carry all sorts of disease, and depending on what part of the country you live in, they can even carry the plague. The plague! Another thing to seriously worry about is house fire.

Sorry to be so alarmist, but having a hoarding neighbor can be a very dangerous thing for you. I don't think you can afford to not get involved. It's mental illness. It's not going to fix itself, it's only gonna get worse.

we have a similar situation with the cats (not the hoarding). we had some leftover "havahart critter ridder" from a major rat infestation (thankfully over, sparked by the former slobs next door moving out and leaving their rats hungry) that we just thought to try - it seems to be working! basically, it is just a shaker of pepper pellets that animals don't like the smell of and we just shook it over our gardens and such.

Holler, you are an entitled, arrogant and ignorant human being. 'I'd find ways of exterminating them myself.' What are you, some kind of sociopath? Unless you do sodium pentothal yourself, there's no "humane way".
Nevertheless, what gives you the right to KILL them, just because you can't find any space in the tiny little stone that passes for your heart, to realize that they have just as much a right to be there as YOU, believe it or not.
They didn't ask to be where they are; they can't help it. But you CAN make better choices, so stop bragging about how you would get rid of them as if it were the best or only choice, and, as if you would actually enjoy it- you just about say you'd have zero remorse anyway.
People like you give the human race a bad name.
And for the other heartless folks who flippantly say "bring them to the shelter":
That is as much a death sentence as any thing else, expediant as it may be for you. They have their lives which are worth something too, much more than your sacred and all-important property. Property is what it is : Props. It's sad that so many people would value inanimate objects.
Why am I ranting like this? I've been rescuing for 15 years and have seen no end to the depravity and ignorance so many people will let themselves sink to, due to laziness, stupidity, and arrogance. I've seen people have no problem poisoning cat after cat, including kittens and nursing mothers who don't care if the kittens are left to die. I've had to peel these sweet and dead, contorted creatures off the pavement with the blood still coming from their mouths and the urine dripping from their bladders, knowing they had one of the most excruciating deaths imaginable.
I've rescued cats which were obviously used as bait for dog-fighting "training"; the bite marks on the face are unmistakable. We never see the kittens and puppies of these "trainings" because they are almost always torn apart and don't make it.
I've rescued cats and kittens who were dumped down incinerator chutes, intentionally boarded up in sheds and abandoned, thrown out off cars on the highway and thrown out of apartment windows. Should I go on? You try doing this for 15 MONTHS and see how you feel about these kinds of people then.

Work with rescue groups, do some TNR, get off your butts and put a little effort into doing something right- simply because it is the right thing to do. We're not living in a third-world country.

And feel free to come at me- I have to throw down with with dog-fighters, drug addicts, viscious people with IQs in the single-digits, and "gangstas" who try to intimidate, ridicule me or express mock pity. I honestly could not care less, and, I can tell you it won't be anything I haven't heard before.

Per the below.