Plant These 14 Thorny Plants to Deter Trespassers

Hard, sharp bushes and other thorn or spine-bearing plants may make life difficult for even the most tenacious invader when they are installed immediately beneath windows. Those without the will or pain-tolerance will probably look for easier alternatives at best.

plant thorns
plant thorns

At worst, the racket caused by the intruder, as well as his efforts to obstruct your passage, will help you buy more time to flee or react appropriately.

Under windows or adjacent to doors, protective shrubs may be used to block, slow, or channel attackers’ movements or repulse trespassers.

If bad guys have to deal with the gnarliest of spiky plants, they’ll think twice before trying their luck on your property!

You’ll have some research to do before you spend money or plant seeds in the hopes of building an unbreachable natural barrier, just like with any other fortification.

Luckily, we are here with a guide on 12 of the sharpest, meanest and most effective plants on earth that can serve as living barriers around your home and property.

Will Plants Really Do the Job as a Barrier Against Trespassers?

Certainly! While some spiny-studded species of flora might be beautiful, they are typically impenetrable and hazardous to cross or go around.

In certain circumstances, plants may even be more formidable than traditional security barriers! Anyone who has ever had a bad run-in with a truly vicious tangle of thorns will agree!

A row of hefty cacti or a towering clump of brambles may frequently be enough to deter an intruder from crossing your property line.

Every location has a suitable climate for certain sorts of plant life that can be used to keep people out.

All we have to do now is figure out which plants will work in our climate and how they will fulfill our particular demands, whether it’s around the perimeter of our property or immediately outside potential entrances to our home.

You might expect that this would be both easier and more difficult than using conventional barricades and other defensive procedures, but you’ll be surprised at how simple and satisfying it is with the right information and a little bit of prepper ingenuity!

Selection Criteria for Security Plants

There is a solution to every problem, and a plant for every unique security requirement. The trick is figuring out which one is right for you!

While certain plants, such as roses, can certainly cause damage and tear and scratch at clothes and skin in addition to causing pain, others like devil’s thorn and firethorn have positively horrible spines that will dish out significant puncture wounds and entangle anyone attempting to go through them, much like modern concertina wire!

You should be quick to contact your local greenhouse or nursery to learn about the appropriate species no matter where you reside.

Once you’ve found a plant that will thrive in your area, double-check that it’ll get along with any nearby species, perform an acceptable soil test and then fertilize with the best fertilizer to ensure your new “border guards” grows nice, robust and fast.

When it’s time to plant, you’ll have to decide whether to spend time and effort while saving money by planting a seed, sprouting or sapling, then waiting for it to develop before caring for it, or trading savings for speed on more mature cultivars that are ready to do their jobs from the get-go.

Plants are living things that need to be fed and protected from pests and parasites, so this might be quite an expense for a barrier that is less sturdy than others. They can also be defeated quickly with power tools, fire, or other special methods of removal.

However, this is usually a trifling concern since most opportunistic thugs don’t want to risk that kind of attention!

Also, thorns are apathetic to whether they are piercing an intruder, your dog or cat, or a little kid.

While these are one of the most beautiful and friendly-looking defenses available, there are definite and certain dangers you should consider as a part of a well-rounded plan.

12 Thorny Plants Perfect for Deterring Trespassers

Porcupine tomato

This South and Central American vine is a truly intimidating barrier, since the foot-long thorns are particularly sharp and strong.

Devil’s Thorn

The source of the popular legend about spiny flora causing its victims to “bleed from every pore,” this African plant has wicked spikes that can draw blood with a casual touch!


a rose bush with yellow roses
a rose bush with yellow roses

While we usually think of the fragrant and elegant flower as a lovely gift or decoration rather than a noxious barrier, thorns were bred into most species over time for just such protective purposes.

Tiger Trap Shrub

This is usually far too expensive to plant as an outdoor deterrent, but those who can afford it swear by its effectiveness at stopping intruders dead in their tracks!

It is truly one of the toughest barriers on this list and must be cut down with special tools like saws and machetes.


This floriferous ornamental is a common feature for fences and walls in tropical regions or perfect for a reasonably-sized home garden. It also serves as a great source of fruit!


juniper berry bush
juniper berry bush

Junipers produce sharp needles that can pierce skin and clothing, making them hazardous to humans.

Junipers thrive in a variety of climates across the world, so there’s a good chance one will suit your needs.



Sharp thorns on hardy desert succulents make excellent barriers against people and animals; they are drought tolerant and don’t need a lot of water.

Slow growing by nature, but there are many forms available that may be used in ornamental or defensive applications.

Pyracantha (Firethorn)

The Himalayan blackberry, or red sandalwood, is a shrub with thorns and crimson orange berries that are highly poisonous.

More significantly for us, it has spines that can grow up to four inches in length. This plant is quite hardy and difficult to chop or break; it can easily tower over man height.


This lovely deciduous ornamental has hooked thorns and impenetrable foliage that make it a tremendous deterrent. It also produces small, inedible berries that are mildly toxic.



Hawthorns are thorny trees that can reach a height of about 10 feet and a spread of 10-30 feet. It may be used to make a natural fence around your yard, as well as being an effective bird and animal deterrent.

Crown of Thorns

This is a South American plant with an extremely tough spiral of sharp thorns on all sides, and it even includes stinging sap that is ready to harm any intruder. It can be used as a hedge or barrier but will require support to reach its full height.

There’s no way to manage this plant safely! Thrives in hot, sunny areas and produces red blooms when in season.



The spines of the agave are sharp, dagger-shaped leaves. It may be used as a wall or fence plant to keep people and animals at bay. Some societies utilize thorns for sewing needles because they are so powerful!


Brambles are a species of thorny shrubs that includes blackberries and raspberries. These reach heights of around five feet with a fast growth rate, a broad spread, and a reasonable stature.

You’ll also get delectable fruits for your effort, but trimming them might be difficult.



The berries are poisonous, sharp-toothed leaves are found on an evergreen shrub with spiny foliage and red fruit.

This is one of the less aggressive plants on our list, and it makes a lot of noise when disturbed, perfect for alerting you to the presence of an intruder.

Questions to Ask Before Choosing a Plant

After reviewing the list above, the choices and options might seem endless, and more than a little intimidating if you aren’t an accomplished green thumb! Don’t worry, as selecting the right plant is just a matter of asking the right questions in context for your needs

The thorns, spikes, or prickles on the plant. How sharp and painful are they? Will they catch clothing and scratch skin, or cause genuine lacerations and puncture wounds on persons who walk into them?

The plant’s typical maximum size. Will it be big enough to keep people away? Is there sufficient space near a door or window for it to grow? Does it grow sufficiently large and thick to fulfill the shape criteria as a hedge or fence?

The thickness or fullness of the foliage. What will the vegetation be like? How thick will the leaves be? Will it provide visual obstruction on the other side? How difficult will it be to trim and shape it?

The rate at which the plant grows. How quickly will it achieve its full size? When will it be able to provide any protective value? Will you save time by planting seeds or buying immature plants, or will you have to spend a lot of money to get a viable plant?

Plant varieties that are suitable for your region. Make sure the plants you choose will thrive in your climate and soil type. Some plants are pickier than others, and some might not grow well in conditions that are too hot, dry, shady or breezy.

The color and shape of the plant. Will it blend in with its surroundings, or will it stand out among other plants? Is it pleasant if aesthetics are a high priority for your home?

Cost is a significant consideration. There is always a price tag associated with adding plants for security reasons, just like any other product. You’ll need to add the cost of plants, if applicable, as well as any irrigation and maintenance expenses.

The ideal approach to figure out which plants are appropriate for security purposes is to talk with other like-minded preppers in your region. There’s a good chance someone has already solved this issue, and can offer helpful suggestions.

That does it for the all the questions you need to ask yourself, or a prospective nursery, before you commit to installing your own living wall of barbed “wire!”


You now know how to choose and cultivate plants that will deter intruders.

Remember that the most important aspect of plant selection is to pick plants that are appropriate for your region and soil type, as well as the plant’s size, density, and overall ferocity.

With a little diligence, you can enjoy greatly increased security from plants that will compliment the aesthetics of your home or property. Have fun planting and don’t forget your gloves!

thorny plants Pinterest image

1 thought on “Plant These 14 Thorny Plants to Deter Trespassers”

  1. Hi Tom, as long as you were looking these plants up, it would have been nice if you would have included the growing zone for each one of them. Then we could look up those in our zone to see if our soils and rainfall are compatible. Would save us a lot of time. Nice to know about those plants though. Thanks.


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