HERB-201 Lessons

Year Two, Lesson Three
Hands-on Herbology

Introduction
Hello again, my lovely young herbologists! Today is a jam-packed lesson, as always. Yes, I know, I know. I do have a tendency to go on a bit, but there’s simply so much to cover as you journey on to become accomplished in the herbal arts. Specifically, today we will be covering processes that thin out your garden: weeding and pruning. We will also touch on magical and non-magical plant diseases, as they are a common reason pruning is necessary. Without further ado, let’s get started!

Weeding
To be frank for a moment, I must address the fact that some of the plants we grow are, well, weeds. This may seem odd to you, as you may feel that weeds are something to be plucked from a garden, not planted there purposefully. Really, the terms “weed” and “weeding” are relative. In the herbological community, and even amongst average gardeners, a weed is simply a plant that is in the wrong place. Did you plant peppermint in the left plot, only to find it cropping up amongst your silverweed? In this case, peppermint is a weed. You’ll likely want to think about weeding the peppermint so that it does not take over. In a more general and typical sense, most of the plants that spread aggressively to areas where they were neither planted nor wanted are commonly considered weeds.

Weeding out unwanted plants is crucial, as otherwise your preferred plant will be competing with the unwelcome visitor for sunlight, water, and soil nutrients. Weeding is particularly necessary for aggressive or invasive plants (which we will be covering later on this year), as they will actually take over the area and choke other plants until they die. To properly weed, you must ensure that you pull up the entire root structure, as even if small portions of the roots remain, they can regrow completely. Secondly, though it may seem counterintuitive, wait to weed until after you have watered your greenhouse plants (or until after it has rained in your garden). When the soil is moist, it will be easier to yank the plants out. Sadly, there are no fancy tricks or spells to help you with this sort of work, though I have seen some intrepid -- or some might say impatient -- young herbologists using the Gouging Charm to till and weed large portions of ground at a time. This displaces tons of dirt, which is very difficult to put back in the right area. More importantly, any rocks hidden in the soil will also fly through the air, potentially hitting you, a colleague, or a passerby. However, there are projects that aim at creating potions that can weed for you by eliminating the undesired plant. Though because one herbologist’s weed is another herbologist’s crop, it is a rather tricky endeavor; they cannot simply make a potion that eradicates a particular kind of plant, as some people will not want that one to be removed!

Pruning
Pruning is another way of making sure your plants’ growth is not stunted. However, instead of removing other plants, you remove portions of the plant itself that are detrimental. For example, a Fanged Geranium with dozens of limp, dry, dead leaves is wasting a lot of energy on those lifeless bits. To ensure that all energy and nutrients are being used on the parts of the plant that are still living, you need to prune. Another time when pruning is necessary is when specific parts of your plant get eaten by pests (as we talked about last week), or when your plant becomes diseased. In some cases, cutting off and removing the diseased portion can prevent the spread to the rest of the plant, though other times there is nothing to be done. Lastly, pruning is also occasionally done for aesthetic reasons. For example, if you want to encourage a tree, shrub, or flower to grow in a specific fashion or direction, you might snip off perfectly healthy areas to force it to grow in that shape.

To start, I would like to mention that light pruning -- removing dead, discoloured leaves, withered flowers, and obviously diseased portions -- can and should be done at any time. Light pruning is commonly referred to as “deadheading.”  The more intense side of pruning -- removing whole stems or limbs, or a large portion of the plant -- is the kind that has specific guidelines.

First, never prune a plant classified as an evergreen! If you’re wondering why, it’s because pruning these plants places significant stress on their health and can damage them. Some very experienced herbologists and gardeners do trim evergreens, usually in the form of hedges, but it requires compensations and specific considerations, so you should not attempt it (nor should you have any need to in your time here at Hogwarts). Trees, shrubs, and vines that flower in summer and fall should generally be pruned in their dormant season during the winter. In the cases of those that bloom during the spring, you should prune as soon as the flowers start to fade. However, in these very broad categories, there are quite a few exceptions. Roses and hydrangeas, for example, have more distinct pruning needs, though they vary by the species or type that you are growing. Another note is to be careful not to prune your plants before the first frost, though it may be tempting to get your pruning done early as soon as the first signs of winter appear. Doing so will leave the newly pruned areas vulnerable to frosts and may damage the plant, which is why dormancy pruning is best done towards the end of winter.

As far as tools go, sharp and clean is an absolute must. Sharp tools will mean less work for you, and an easy cut that will heal faster. Cleanliness is an important factor as you can spread diseases from branch to branch and plant to plant if you don't keep things clean. Use your hands (if safe) to check for dead leaves, flowers, or limbs. Remove them with either pruning shears or hand shears, though in many cases, some dead leaves may fall at your touch. Also, though it may be obvious, if a new bud is forming, you should cut around that to save that portion! Make your cuts facing away from you and flush with the limb’s joint, if possible. When you finish pruning, it is important that you give the plant more fertilizer and place it out of direct sunlight until the cuts have begun to heal. If the plant cannot be moved, such as in the case of greenhouse beds, you will need to be adept with your Darkening Charm!

On the topic of charms, when dealing with dangerous or poisonous plants, or plants that simply don’t take well to being touched, herbologists can employ the Severing Charm to prune them instead of the traditional hand tools. Of course, the spell cannot completely replace hand tools, as if a plant accidentally lashes out in a way you didn’t anticipate, you can end up cutting through the wrong area. Some day, I should tell you all of the first time I had to prune the Whomping Willow -- we both still have scars from that afternoon! Additionally, when working with magically resistant or magically reactive plants (particularly in the case of those used for potions), you’ll want to limit the amount of magic used on or around them, opting for hand tools instead. I know you have already covered the spell in charms, but here are the details in case you have forgotten. Keep in mind that tree limbs will likely require more than one cast of the spell, though this can be mitigated by increasing willpower as you advance through the years.

Diseases
As we discussed, diseases are one of the main reasons to prune, other than to promote growth. There are many diseases that can affect your greenery, such as root rot, silverleaf, mildew, Bubotuber blight, and poison pox. Not all of these blights can be solved via pruning -- some are unavoidably fatal, while others require special care to reverse the effects. However, it is pertinent to discuss them in this lesson regardless.

Dutch Elm Disease
This disease is fungal and most often transferred by a type of beetle called the elm bark beetle. The name comes from its initial discovery in a Dutch elm tree in the Netherlands and is not related to the disease's infection. For this reason, many choose to call it simply “elm disease” to avoid confusion. This disease can be recognized easily by the strange spidery patterns that it causes in the bark, as well as how it causes the branches and leaves of a tree to wither and leaves to yellow and die out of season. The dying of the tree is slow and can take up to twenty years. The branches die first, then the roots are taken over. When the roots die, the tree is unable to supply water to the rest of the plant, which eventually causes a full biological death. To heal the elm, herbologists and potioneers have developed an oily substance which can be used to coat the tree, preventing the fungus from spreading. Infected areas of the tree should be pruned and disposed of immediately.

Root Rot
Not to be confused with rat root -- a plant we will cover later on in your studies -- this disease can affect nearly any plant. Plants that are particularly susceptible are those that require very little water or are vulnerable to overwatering.This is also a significant concern in plants that have poor drainage. Root rot occurs when a plant is watered to a point where the roots are sitting in the excess moisture for long enough that they begin to rot and mold begins to grow on them. Simple, no? Obvious signs that root rot has taken hold are a sudden wilting of plants which, admittedly, is a bit of a vague symptom. A much clearer sign can be found if you’re willing to dig up your plants. The plants I have up front show a progression of root rot, the leftmost being completely healthy and the rightmost being completely afflicted.

To avoid this problem, make sure you are not overwatering your plant and that your plant has good drainage. Sadly, if your plant is afflicted with root rot, there is not much that can be done, and the afflicted plant should be removed from contact with any healthy plants, lest the mold spread, and some brand of fungicidal potion applied for good measure.

Silverleaf
This disease develops in both magical and non-magical trees, starting out as a light crust on the wood. It is yet another example of a fungal-based disease, which you will soon see is a common trend. The telltale signs that your plant is afflicted with this ailment is that the leaves on affected branches will begin to turn silver, hence the name. The scab-like crusts, pictured to the right, are also quite distinctive. Should a plant become afflicted with silverleaf, be quick to prune all affected branches as soon as possible, as it spreads easily and is often fatal. If you can catch it early enough, you can spray the visibly affected areas with Cantanker’s Crust-Lifter. However, this is only recommended for very early stages or lightly affected areas, as once the limb is taken over with more than a few specks of the crust-like formations, the potion will do little other than slow the disease’s progression.

Poison Pox
A bit of a misnomer, this spore-borne disease affects solely plants with a venomous capacity. That is, plants that bite and inflict their poison on beings, beasts, or even other plants. Those in the more general group of toxic or poisonous plants, such as belladonna or aconite, are not affected. In its earliest stages, this disease has very few telltale signs, only characterised with a general drooping and wilting of the plant’s stems, flowers, and other extremities. As the disease progresses, however, more obvious signs appear, such as the plant’s teeth and fangs -- if it possesses any -- crumbling and cracking and the leaves turning a bit waxy and oily. Finally, during its last stages, the disease is characterized by dark purple veins appearing along the stem and leaves of the plant.

If caught early, the plant can be quickly restored back to full health with Toxeputus Depello, a potion specifically developed by Annalise Merryweather in 1851 after much study of the disease-causing spores. However, if the teeth have already started to crack, or the plant has begun to feel oily to the touch, extreme care will need to be taken. At this point, it is best to prune any and all diseased portions, or if the entire plant has succumbed, to prune all but one stalk. Then, the soil in which the plant is growing must be treated using the Disinfecting Charm. You may also wish to create some suds in the dirt with the Scouring Charm. As none of this is terribly good for the plant, it may not survive the treatment, and it may take up to several months to nurse it completely back to health with a strict regimen of special attention, fertilizer, and weekly doses of Toxeputus Depello. Should any part of the plant be allowed to lapse into the last stages, the entire plant should be removed from the vicinity of any healthy specimens, as there is no saving it. The spell itself is not difficult as long as you are not trying to affect large areas.

Bubotuber Blight
Not actually transmitted by its namesake, this disease is another misnomer. Bubotuber blight is named as such due to the boil-like yellow-green pustules that sprout all over afflicted plants. This disease specifically targets magical plants, though many herbologists are worried about the potential development of a new non-magical strain that we would have to equip Muggles for. It spreads quickly, affecting all parts of the plant. Because of this, it is important to quickly prune all affected parts to keep it from spreading. Once you have done so, apply Beauregard’s Blight-Be-Gone -- a popular potion used for more general types of blight -- to ensure that all traces of the disease are gone and it will not crop up again!

Elecano Stembrek Disease (ESD)
While this is not necessarily a common disease, and hopefully not one you will encounter in your time here at Hogwarts -- Merlin’s mercy, I wouldn’t want an outbreak of that in my greenhouses --  Elecano Stembrek’s Disease is an absolutely crucial disease to cover. The term “Stembrek’s Disease” was coined by 16th century herbologist Ignac Stembrek, who was able to “connect the dots” in terms of many seemingly unrelated magical plants losing their abilities. However, the specifics of the disease remained a mystery until a more recent breakthrough by a team of herbological researchers led by Tamsin Elecano. After nearly 400 years since its discovery, Elecano -- a half-blood who harbored a love for Muggle branches of science into her adulthood -- finally identified the cause of the disease: a virus. 

The disease thrives off of magic, much like the Chizpurfle, however, it does not devour it. Instead, the disease seems to attack the “essence” of the plant, or the “X factor” that makes it magical, though that is a rather foggy concept at best. Theory aside, there are some very clear consequences for your plants if they contract this virus. ESD first affects the stem of the plant, hollowing out the centre until the stem wall is so thin that you can break through it with a touch. In some cases, ESD attacks the roots as well, turning them an orange or a pinky-yellow colour, often causing the plant to take on a sickly pale color, and preventing further growth. Over time, the disease takes away all magical ability from the plant. For example, Devil's Snare weakens and loses the ability to strangle and move. A dandelion's seeds lose their wish-granting properties, and Gillyweed no longer transforms the body to allow for breathing underwater.

There hasn’t been much research into this area due to previous beliefs that it was incurable and highly contagious (and therefore most outbreaks were promptly vanished or the plants killed off and disposed of in some way). However, it has since been discovered that a plant with ESD is salvageable, and one of the most common suggested treatments is withholding water. The virus needs a host to survive, and the treatment of withholding water kills the virus by, essentially, killing the host plant. Ideally, one would just weaken the plant to the point where the virus dies off and then gradually bring the plant back to full health, but there is significant skepticism in the field as to whether this is even a viable method¹, and those that do believe it is possible to feel it is not worth the considerable effort of bringing the plant back from its deathbed and therefore do not bother. There are currently no preventative measures to ward off this virus, but fortunately it is relatively uncommon.

Abyssinian Shrivelfig
With the theory out of the way, I would like to take the rest of the class to look at a magical plant called the Shrivelfig. Classified as a fruit -- among other things -- this plant grows natively in Abyssinia, though they also grow well enough in Persia and Mediterranean countries. Because of this, they require a pH of roughly 6.1 to 6.5. The plant requires full sun and, while young and growing, should be watered regularly. However, once the tree is fully established and growing well as a sapling, you should water deeply but infrequently (roughly every one to two weeks). When fully ripe, the fruit has a purple or deep red hue. Shrivelfigs grow on trees up to a height of ten metres and produce tens of Shrivelfigs per limb. Interestingly, the “fruit” of the Shrivelfigs is actually just a fleshy pod that houses both flowers and a runny, purple liquid (also sometimes referred to as sap). The plant must be skinned carefully to get to the center without ruining the delicate flowers. Its roots are quite hardy, meaning that they are both drought and cold resistant, making them good for growing all around the world, though none can match the homegrown specimens.

The sap and flower petals are widely used in the Shrinking Solutions and have recently been used in some versions of aging potions as well. The effects are so powerful that should you consume the Shrivelfig sap, your tongue and/or teeth will reduce in size, and you will have a noticeable pucker for the rest of the day. If you have nothing else to do, Shrivelfigs may be utilized in a delicious, though mouth-puckering jam. The leaves, on the other hand, enjoy popularity in wart removing potions as well as potions to aid with rashes. When harvesting, it is preferable to have a steady hand and expert skill with the Severing Charm, particularly if your tree is quite tall. When pruning, you should watch for the usual things: withered leaves and dead twigs where no leaves are growing, as well as diseased portions.

Closing
That is all, class! Apart from your practical assignment, that is. This week, I have a Shrivelfig you will need to tend to. I hope you have enjoyed today’s look at herbal diseases and ways to thin out your greenery and feel more confident about meeting the challenges that herbologists face on a daily basis!

Footnotes

1. There is some doubt as to whether the studies of this remedy were performed on plants that actually had the disease. The plants used were documented as just in the first stages of the diseases, and skeptics therefore suggest that the disease was misidentified, and there was no Elecano Stembrek’s present in the first place.

 Original lesson written by Professor Venita Wessex
Additional portions written or inspired by Professor Lily Tudor
Image credits here, here, here, here, here, here, and here