How do you keep people out of your garden?

I have a corner house with a moderate amount of foot traffic running in front. I seem to have a problem with people thinking they can just pick whatever flowers they want from my cottage style garden, which normally isn't that big of a deal as most of my stuff produces bloom all summer, but some inconsiderate person decimated my allium and I am done playing nice. Last night I entertained notions of planting poison ivy among my plants, or surrounding a garden stake with a spiral of barbed wire for next year's allium to safely grow inside of. I would love a fence, but it is out of the budget. Any suggestions?

I would try putting up a sign first "please do not pick flowers" or "Stay off the grass" or "Private Property" if you want to try the polite approach. There are motion sensor alarms that are designed to scare off wildlife, they might cause a person to think twice about picking the flowers if they think it draws attention to them and they might get caught. Or you could try the direct approach and tell these people in person (if you catch them in the act, that is) Try a fake security camera, or even a real one, they aren't so expensive and are fairly easy to hook up.
We had a similar problem with people fishing in our pond, it got to the point where 8-10 people were down there at a time, and leaving their garbage and just being a general nuisance. So we put up signs, "Posted- No hunting, fishing, trespassing , ect. and I was surprised by how effective it actually was. So it never hurts to try, it just might work. Good luck!

Yes, try the nice approach, even offering seeds or cuttings if people want to grow their own flowers after admiring yours.

The motion activated sprinkler is an interesting idea, but it cannot tell who is legitimate (mail or package delivery, friends...) vs who is there to molest the flowers. Aim it just right, to miss the walkway if possible.

It is very sad when others dont appreciate the work, the cost or the time you have taken to make a nice garden for ALL to see BUT from a distance. I'm not sure IF you could report this damage to your garden to the police, neighbourhood watch, or even try set up a neighbourhood watch for your own street, maybe others in the street / road are having problems too. your local police may be interested in helping you get started, I know here in UK, the drop in anti social behaviour has made a huge difference and it helps keep the police informed but also allows them to get on with dealing with other police matters.

It appears this problem you have is universal, I remember when we began building our home around 30 years ago, as the building was taking shape, I decided to start lay out the garden, (we were recovering an old 150 year old large estate garden with walled gardens, long driveways and magnificent sea views, we had old photographs to guide us in some places,
I drove there crack of dawn each morning and began to plant loads of shrubs, Rhododendrons, Azalea's, Camellias and many more plantings, I arrived one lovely sunny day to find most of my plants had been dug up, whoever did this must have been local as they even took my wheelbarrow to help cart off the plants, these plants still had there name tags, AND price ticket, believe me, I know how you feel, I was absolutely devastated, my heart was sinking, I had no neighbours at that time a single track road / drive, I called the police and all they could tell me was, someone must know your laying out a garden and helped themselves, JEEEEES, I didn't need a genius to work that out, we never did find who did this BUT they never returned, We had spent a fortune (fortune to us) on these plants not to mention travelling to different nurseries to look, search and purchase them.
I hope you can find some help, it's so disgusting,
What about a cheep battery alarm to sound off when someone approaches, not sat too low or any animals will set it off, it might just be enough to make the person / people know your aware they are around. Try NOT to get confrontational as this can lead to a much larger problem, those people sometimes DON'T think they are in the wrong LOL.
Good luck. Please don't give up your gardening as it obviously gives you much pleasure.

Kindest Regards.
WeeNel.

Here's another (possible?) solution that you can combine with the signs you put up.

Spray your flowers occasionally with something like Liquid Fence, which is a (very smelly) Deer repellent. Once the smell subsides it won't bother you, but if the flowers someone picks are stinky, it may make them think twice.

I'm not suggesting you do this forever. I may only take a few times if it's the same people doing the picking.

Thanks for the suggestions, as it turns out my partner was so irritated about the allium (it was the favorite apparently) we are going to shift some things around and go for a fence next year. But I am sure we will still have to educate some people in the future. I think I am going to use some scrap wood to make some little vintagey signs though. Thanks everyone!

It sounds like a fence may be the best option. Best of luck in the meantime.I hope you can keep those people from picking your posies.
It never ceases to amaze me how bold (and inconsiderate) people can be. I would probably "go off" on someone that I caught defiling one of my flower gardens.

Plant the smelliest or most irritating plants out near the fence so they will billow and grow through the fence. Then, whoever thinks they want some cuttings will get the smelly leaves, or itchy hands and arms.

My neighbor apparently had problems with people just walking by his prior house and ripping stuff out just to throw it on the ground, so he moved all the plants inward and lined the sidewalk with raspberry bushes. Not too long after that he was enjoying his day when some punk came running by and tried to quickly rip a bunch of canes off; there was a lot of swearing and a lot of laughing according to my neighbor.

LOL