Are Lemon Tree Thorns Poisonous?

Citrus trees, like Lemon Trees, are great plants to grow in your backyard. They provide wonderful smells when they flower, and give you plenty of delicious food to eat. 

However, if you have worked with citrus trees of any kind before, you may have noticed that most of them have thorns. Unfortunately, even thornless varieties aren’t truly thornless, but just have fewer thorns than the average tree. So do you have to worry about any danger from the thorns?

Lemon Tree thorns are not poisonous and don’t contain any other harmful compounds. The only exceptions are if you are allergic to lemons or lemon oils or if there are bacteria on the thorns that could then enter your skin. This means it is the wound itself that poses the biggest danger over the thorn. To prevent injuries, you may want to wear thick clothing and gloves. 

Why Is My Lemon Tree Growing Thorns?

It is normal for most citrus fruit trees to grow thorns, including oranges, grapefruits, kumquats, and even lemons. These thorns used to be sharp and plentiful, but many growers are trying to breed the thorns out of these citrus trees to make life easier for gardeners. 

While they haven’t completely eradicated thorns on Lemon Trees, many Lemon Trees have softer or less prominent thorns. For example, Meyer Lemons, one of the most common breeds of lemons, have small and soft thorns. While you can still get caught on them, it is much less likely. 

Two breeds of lemons are considered to be thornless. These are the Eureka and the Bearss Lemon. It should be noted that while they are considered thornless it is actually that they have fewer thorns. If you have one of these varieties, don’t be surprised if you still find a couple of thorns occasionally. 

These thorns were designed originally to protect the trees from herbivores that might want to snack on their fruits. They may also have helped store water in drier climates. 

One of the reasons it is so hard to breed out thorns is that most citrus fruits that have little to no thorns tend to not produce as much fruit. Sometimes the taste is also lacking compared to other varieties. 

What Type of Lemon Tree Has Thorns?

Lemon stem with thorns
Theoretically, all Lemon Trees have thorns. Even the thornless varieties just have fewer thorns than the average Lemon Tree. Lisbon Lemons are considered a very thorny variety, especially compared to the Eureka version, which is mostly thornless. 

Are Lemon Trees Toxic to Humans?

There is no part of a Lemon Tree that is toxic to humans. This includes the fruit, leaves, branches, and even the thorns. If you get pricked by the thorns of a Lemon Tree, don’t worry, as you won’t see any signs of toxicity or poison. 

However, it is worth noting that Lemon Trees are toxic to a majority of animals we keep as pets, including dogs, cats, and horses. While usually one lemon or some roots won’t be life-threatening, they can have some serious side effects, like vomiting and diarrhea. 

The thorns are usually okay, as long as your pet doesn’t eat them. They won’t be poisoned by being pricked. However, they can get injured from the sharp thorns, and may develop an infection if the wound isn’t treated properly. 

Why Do Lemon Tree Thorns Hurt?

Like most other plants with thorns, Lemon Trees have sharp thorns. With the exception of a few varieties, Lemon Tree thorns are rigid and sharp, so you can easily prick or puncture the skin. Even though there isn’t any toxicity, the breaking of the skin can cause injury and pain. 

Additionally, the thorn may be harboring bacteria, which can cause an infection, so if you leave it untreated, your pain may grow and become more irritating over time. Most of the time, these scratches or pricks are minor, and people forget about them or brush them off, especially if you get cut often. 

However, if not taken care of, you may risk sepsis, and pain and swelling in the area. There are many reports of farmers and gardeners getting serious injuries from working around their plants and experiencing minor injuries on a daily basis. 

How Do You Treat Thorn Pricks?

One of the best things to do is practice avoidance. If you can, look at getting a pair of thick gloves to protect your hands and wrists. Goatskin is considered to be more resistant to punctures than other kinds.

You can also wear thick clothes and glasses to protect your eyes. Doctors also recommend making sure you are up-to-date with your tetanus vaccine. While it is a rare possibility, there have been cases of people getting tetanus from their plants. 

However, if you’ve already been pricked, the best case is to treat it like any other injury. Immediately go inside and wash the wound thoroughly with soap and water. Then cover the open wound with a Band-Aid to prevent any more bacteria from getting in. 

If you start to notice any strange sensations, rashes, or discoloration around the wound in the days after getting injured, it is best to go to a doctor right away to make sure it isn’t anything serious. 

Can People Have an Allergic Reaction to Lemon Tree Thorns?

Skin rash
It is possible for people who have allergies to lemons and lemon oils to have a worse reaction to getting scraped by a thorn. This is because lemon oil contains terpenes, similar to poison ivy. You can usually tell it is an allergic reaction over a bacterial infection because allergic reactions usually happen much sooner, within hours. 

If you know you are allergic to lemon oils or think that might be the case, you can put antihistamine lotion on your skin around the injury, and take medicine like Benadryl to reduce symptoms. If you have severe allergic reactions or you are struggling to breathe, go to an emergency room right away. 

Should I Cut the Thorns off of a Lemon Tree?

Cutting the thorns off of a Lemon Tree doesn’t pose any harm to the tree. You don’t want to cut off all the thorns at once, especially on varieties that have a lot of thorns, as this could hurt the tree and cause slower growth. Cutting off thorns where you are working isn’t a problem. 

Most people do this around the same time they are pruning. This allows them to get rid of everything all at once, and the Lemon Tree can heal before the growing season. Once you have cut them all off, you can start pruning them as they appear, which can be much easier. 

When Should You Not Prune a Lemon Tree?

You should never prune during the harvest season unless it is an emergency. Generally, the best time is right after a harvest of the fruits, as this gives your Lemon Tree plenty of time to recover. 

If you are in a warmer climate, you can prune any time it isn’t a high temperature, but know that doing it just before or during the growing season will reduce your fruit yield and may cause your Lemon Tree to grow slower. 


While being pricked by a thorn can be pretty frustrating, as long as you can clean the wound thoroughly, you don’t have to worry about much danger. There are no poisons or toxins present in Lemon Tree thorns that could cause danger to you or your family. 

However, Lemon Trees are toxic to many pets like cats, dogs, and horses. It is important to make sure your pet stays away from any Lemon Trees to avoid ingesting the lemons or being hurt by a thorn.

If you want to be extra safe and avoid the sharp thorns, you can simply cut them off along with your regular pruning. Just make sure you preventing pests and giving them enough water, as their thorns help to protect them in the wild.