Lesson Four

Welcome to our final lesson. I know you've all been looking forward to venturing into greenhouse 3 all term and it's finally time. Before we go in, I need you all to remember that the plants here pose a real risk to your safety if you do not treat them with respect and caution. Any reckless behaviour will lead to you being asked to leave.

There are several reasons as to why certain plants might have developed characteristics that pose a real risk to us. A single plant might have more than one of these factors at play.

The first and most common is that the risky characteristic is a defence mechanism. A defence mechanism is something about the plant that it uses to try to persuade you to leave it alone. Thorns, prickles, spines, trichomes (the spiky structure on some leaves that give nettle's their sting), and nasty chemicals within the plant itself are all common defence mechanisms. If you think back to lessons 2 and 3, the Mimbulus Mimbletonia and bubotuber use disgusting substances as a defence: the spray of liquid shocks you and disgusts you with a nasty smell so that you're far less likely to go near the plant again. Even non-magical plants can have dangerous defence mechanisms. It simply becomes more acute for magical plants as magic can make the mechanism just that much more dangerous (for instance, magic can let a plant move a lot more and even sense you coming). Think of fanged geraniums: the simple addition of some teeth turns a pot plant into something that could cost you a finger.

The second reason is closely connected to this. Some plants are dangerous because they're poisonous when you eat or drink them (or in some nasty cases, just stand too close). This could be because the poison is intended as a defence mechanism to stop animals from grazing on the plant or it could simply just be a quirk of chemistry. Some magical plants are more powerfully toxic because of their magical properties. Others are dangerous because they can be combined into a potion with destructive effects.

The last reason is that some plants are carnivorous (they eat meat to stay alive, rather than getting all their nutrients from the soil) or simply naturally inclined to kill. They may be aggressive for the simple reason that they're trying to eat you (or possibly even kill you just for the sake of it - with some plants we're still not entirely sure). While carnivorous plants exist in the non-magical world as well (I have a fascinating Venus Flytrap on my desk if anyone is interested), they can't usually snack on humans. Magic changes that.

With that in mind, let's tour the more lethal plants in the Hogwarts collection. Please don't touch and don't get too close. I'll be watching.

Poisons

This is the poisons bed (yes, there are quite a few of them). All of these are considered magical plants because they can be used for magical purposes, such as brewing potions (rather than being magical in themselves). For the sake of time, we'll look at just two of the more deadly ones today:

Aconite - Also called Monkshood and Wolfsbane (because it was used in the middle ages to poison wolves), this plant has purple flowers. The flowers and roots can be used in potion-making (notably in the wolfsbane potion which helps those suffering from lycanthropy), but the green leaves are highly toxic.

Belladonna - also called deadly nightshade, this is another plant with purple flowers and green leaves; it also has black berries. Most parts of the plant are highly poisonous. However, the essence of belladonna (correctly diluted) is prized as a potions ingredient. It is known to cause hallucinations which is why it was associated with witchcraft, as I mentioned in lesson 3.

Care Tips: Keep them well watered and make sure you weed the bed very carefully so as not to disturb them.

Snargaluff

This isn't a wizened old stump we've kept in here by accident. It is in fact a very dangerous and vicious plant called a snargaluff. If interfered with, it will lash out at you with prickly vines that can move far faster than you can and that cause significant damage (it's one of the nastier and more dangerous defence mechanisms you'll find).

You may be wondering why anyone ever goes near them. The answer is that they grow pods in an opening at their centre, protected by those vines (the opening can also slam shut, trapping your arm). Those pods resemble a green, pulsating grapefruit and are very useful for potion making; you must break them open to extract the juice and will find large quantities of wriggling green tubers inside. To retrieve the pods, it is advisable to work in groups so that someone can attempt to deal with the vines while someone else makes a grab for the pod. One of the recognised methods for momentarily disabling a snargaluff is to tie several of the vines together (not a particularly inviting prospect, I have to agree).

Uses: Potions ingredient

Care Tips: Wear protective clothing (including goggles and gloves) and never work alone.

Mandrakes

Mandrakes appear perfectly unremarkable while in the ground, with only a few rounded leaves showing above the soil. If you pull them up though (don't do it now!), you'll find that they're anything but unremarkable. The root is shaped like a small, humanoid figure. The thing that makes them truly remarkable and dangerous though is the sound they make. A mandrake's cry can cause deep unconsciousness (if the plant is a juvenile) or even death (if it is fully mature).

Mandrake's are interesting because they show a certain amount of personality. As they grow, they resemble different stages of human-like development. Young mandrakes are like babies, they go through a stage akin to being a teenager (where they like to have loud parties) and then they mature into adulthood (you'll know they've reached this stage as they will attempt to move in with one another). They are also an incredibly powerful potions ingredient; they can be used to restore people who are suffering severe magical damage, such as petrification.

Uses: Valuable potions ingredient

Care Tips: Repot them regularly as they grow, use plenty of fertiliser, and always wear your earmuffs!

Devil's Snare

This one is behind a magical barrier because straying anywhere near it would be a very bad idea. This is devil's snare which you might remember from when we covered flitterblooms. It has the same writhing sort of tentacle-like creepers/leaves. However, rather than just waving about, those creepers can latch onto you, wrap you from head to toe and suffocate you within minutes.

Devil's snare is one of those plants we're still not entirely sure about. Herbologists cannot agree whether it gets some kind of nutritional value from ensnaring people, is trying to protect itself, or just enjoys throttling living things. What we do know is that it thrives in cold and damp conditions (people often grow it in cellars or caves for this reason). This is especially important to note as your primary defence should it catch hold of you is to conjure light and/or fire as swiftly as you can.

Uses: Sometimes used as a security measure or even a weapon

Care Tips: Keep it well watered and out of direct sunlight. Keep your distance. Should it get hold of you, try to relax your body to prevent it from tightening its grip and conjure fire/light as soon as possible.

Venomous Tentacula

This is another one that will grab you if you get too close so watch your step. This is a fully mature venomous tentacula. You'll note a large amount of groping vines and also the head-like structure at the centre, full of snapping teeth (its bite, as you might have guessed, is highly venomous). You'll also want to look out for the spikes and the shoots as these release poison as well. Nearly every part of this vibrant green plant is dangerous.

The venomous tentacula is a carnivorous plant that also has a certain amount of awareness and intelligence (it can certainly sense when food is passing by). While it tends to consume smaller things like doxies and chizpurfles, it will still snack on you if you give it an opportunity. It uses the vines to seize its prey and direct them towards its jaws. You can use a severing charm to free yourself from the vines but sometimes a sharp slap with your hand or your secateurs will do just fine.

Various parts of the plant can be used in potions. The leaves are particularly prized but the plant also produces a juice that will make someone feel like they're burning from the inside out if swallowed. The seeds are a Class C non-tradable substance; you can recognise them if you ever come across any as they make a soft rattling noise, even if they're perfectly still. As with other plants featured in this lesson, tentaculas are sometimes used as security measures. Some people have gone still further and keep them as pets (no, that wasn't a joke).

Uses: Potions ingredients, security measure.

Care Tips: Make sure you have a good supply of food on hand. Stay out of grabbing range and always wear your gloves and goggles. Juvenile tentaculas can be a particular nuisance when teething so always have an alternative to your arm for them to chew on.