Pyracantha is nasty enough but if neighbors are that thoughtless they will likely trample on ANYTHING u plant

True... but maybe if it scratches their expensive car enough times they will have a change of heart! I will look up Pyracantha. thanks :)

A line of small boulders can be viewed as a sturdy plant. They are hard to trample, can fit neatly (and partially buried) between the sidewalk and the curb (if that's your layout), are unfriendly to parking efforts partially off the street, and they get in the way of people's access to their car passenger doors.

It would be unwise to suggest roofing nails, so I won't.

Another suggestion...Barberries are prickly...I just pruned one and those thorns go thru latex coated gloves.

-Babka

Thanks for the replies. No sidewalk just a hill slope leading from my house down to the street below. You have the right idea about blocking access to the car! I will look into Barberries also.
I saw something called "rhaphithamnus cyanocarpus" online that I liked but can only find it from one place in seed form and I need something I can buy that is already a good size so I can solve this issue speedily.

a Rose Glow Barberry looks just about perfect. Matches the color theme in my yard ( red fountain grass with lavender and santolina) and seems just nasty enough- Can also grow slightly over the curb. Thank you!!

My favorite 'nasty' is Rosa Californica. I live on a corner and have 200 feet of curb. I mined my Cape Honesuckle hedges with R.C. Nobody jumps my fences.

I have Prickly Pear cactus along another fenceline. I planted Cleveland Sage, Lantana, small Crape Myrtles and Matilija Poppy with it. It's a beautiful border.

Ribes speciosum (Fuchsia-flowering Gooseberry) is extremely thorny and gets to about 5' x 5'. It's also native and drought-tolerant as heck. It grows at a moderate rate and might transplant OK from 5 gallon containers.

Another thought: park your car(s) in that spot while your plant is getting established.

This post was edited by OregonGrape on Sun, Apr 20, 14 at 22:42

More great ideas... Thank you.

There are lots of tough, hardy, and beautiful roses that thrive in your area. Another route would be agave, not only do they have nasty thorns if you get the juice on your skin it'll make you break out in hives. I also second the suggestion of using rocks, I love the look of stone in the landscape and it might help protect your thorny plants until they get big and nasty.

Good luck with your project, I hope you can discourage your neighbor and create a beautiful garden at the same time!

I love rocks too- my last home had decomposed granite and natural rocks- big. This wouldn't work where the trouble spot is though at this place. I just saw two HUGE agave plants on craigslist for $40 each. They look 4 ft tall at least. Going to check with my gardener how hard it is to transplant them. Thanks everyone!

Bouganvillia has nasty thorns and if you plant it near the curb, it will reach out into the street pretty quickly.

I agree with nil13; bouganvillia has really big thorns(is also slightly poisonous if it penetrates into the skin)but the nice thing is that this plant 's thorns blend in with the branches. Also, it has really nice flowers for decoration, too(hot pink to purple).

Dyckia Platyphlla Cherry Cola, it is dark, barbed, gorgeous, and mean. Puya plants which are a similar, and related to bromeliads; also barbed, one has turquoise blooms, and Firethorn as mentioned in earlier post. I have one, and I'm afraid of it. You won't grab any of these without whimpering or belting out colorful metaphors.