I am doing a bit of work around our garden, part of which will involve surfacing a largeish area with bark mulch.
There are a lot of cats around our area, and they are already frequently in our garden. I'd like to avoid accidentally creating a large litter tray, and I was wondering if anybody could recommend some plants that may help us to deter the cats from coming in?
Cats will also generally avoid the largest sizes of bark mulch - say, 3-4 inches in diameter or larger. They have a hard time standing on it because it is "tippy" and an even harder time scratching in it, so they tend to find other places to do their business when they can. So if you will use this size, or put a layer of the largest size bark mulch you can find on the top of what you do use, this should at least cut the behavior down.
I've used this method for years (I currently have three cats of my own) even in my potted plants, and found it nearly eliminated the litterboxing behavior. Your mileage may vary, however, because as mentioned in the other note, this is not an easy problem to solve.
Also, fist size or larger cobbles/rocks scattered throughout the planting will help as well. If you can get enough to place them no more than just a few inches apart in the mulch, then there will no longer be a large enough clear area for the cat to do their business. They also won't be able to scratch in the mulch as they prefer to do, so that will be a deterrent to the behavior as well. I've used largish cobbles as another way of keeping cats out of my potted plants. If you can cover enough of the soil with them, this can be very effective.
Ooh dear, I'm veering between being absolutely truthful or coming out with the usual PR nonsense about some plants being 'scaredy cat plants'. I think I'll opt for truth...
No, there are no plants which will deter cats from coming in your garden, and they may well view your bark chips as slightly chunky cat litter, unfortunately. There are plants they don't like much (pelargoniums) but certainly not enough to put them off coming into the garden. What they don't like are stones - not pea shingle, that's too small in size, more like cat litter, but small pebbles. Using those instead of bark will mean they won't attempt to use the area as a toilet because they're too uncomfortable for the cats to push around. Your other option is to use bark chips, but scatter bits of thorny branches over the top (berberis, holly, etc), but only if the area isn't regularly used by children.
I don't know why you're having such a large bark chipped area, there may be a very good reason, but another option is ground cover plants which spread and cover all the soil. Finally, get your own cat - it may well use the garden as a toilet at certain times of year, but will usually prevent other cats from coming in too frequently.
You can always put some chicken wire under your mulch,they do not like too walk on it and they wont be able too scratch it.
Cats supposedly don't enjoy citrus. You could put citrus peels around your plants. You might also mix some citrus oil with water and spray it around. Growing citrus trees might help, but I'm not sure.
Rue is a perennial herb in the citrus family (and it is cold-tolerant). It is also said to deter cats.
The following suggestions don't have to do with planting plants, but may also help:
You could also try getting some strips of papery or plasticy material that sound like large animals moving in the brush when the slightest wind hits it, and have them dangling around in hidden places throughout the yard. That frightens cats. It may also frighten you, though. We had something like that dangling from our eaves, once (I think it was some kind of tape-like material involved in repairing the eaves or the paneling on the house below them.
You could get a dog to patrol your yard. Dogs tend to scare cats away.
Poppies, yarrow and chamomile attract cats (cats like to sleep on them, which is especially harmful to the poppies). So, you may want to avoid or guard those plants.
When we had a cat I would put 3-4 8 inches long pushed 5 inches into the ground. The idea was to make no area large enough for the cat to lie down. That combined with throwing a rock at the cat whenever it was in the garden conditioned them to go elsewhere. (We have 80 acres, and only a thousand square feet of garden.)
