HERB-201 Lessons

Year Two, Lesson Five
Hands-on Herbology

Introduction
Today we will be talking about plants that herbologists often find a hindrance. A garden full of needy plants that require different amounts of sun, water, and soil types is certainly a challenge, but what about plants that won’t stay where you’ve put them? These are called aggressive plants, invasive, or alien plants. Ah, I see a spark of recognition in your eyes. No, these are not plants from the W.H.I.P.S. Class B: Physically Aggressive. These are just plants that will run rampant and grow wherever there is free space (or sometimes where these aren’t!) We’ll start off class with some definitions to give our topic a framework and then go over a few examples of such plants that fit into these categories, as well as strategies for containing them and growing them successfully alongside regular plants with minimal complications.

Invasive and Alien Species
As you know, herbologists face many challenges when getting involved with field work, and alien and invasive species are one of them. The ability to grow foreign or alien species -- also called non-indigenous, introduced, or invasive species -- can seem like a good thing, but can actually be quite dangerous to an ecosystem, as I will outline in a moment. At its most basic, a plant is considered invasive if it can penetrate an area it is not native to, particularly if it can do so quickly and easily. In actuality, many of the plants we discussed in Lessons Five and Six of last year would fall under this category, with motherwort as an example. It was actually native to Asia and parts of southeastern Europe, but it was introduced to the rest of Europe, including the United Kingdom, and then to the United States. The plant adapted well and grows voraciously in the wild, displacing native foliage.

Inherently, there is nothing wrong with an invasive plant. It may be very pretty or easy to grow. It will likely have useful properties, perhaps even properties that were not previously available in the plant life of the area. The trouble lies in the fact that the plant is not native. As we discussed in the last lesson of Year One -- and something that has likely been touched on in your Care of Magical Creatures class -- ecosystems can be very fragile things, and the smallest change can upset them.

To better understand this, we will take a real example. Many female animals, such as Crups, Kneazles, and Nifflers eat Largrass when pregnant to soothe their upset stomach. The normally very spiky and sharp grass stalks are able to recognize the various species which approach it and alter their leaves to be less harsh to avoid cutting the animal’s mouth and digestive system. In turn, the animal spreads the plant’s seeds via their waste or in their fur. Overall, it is a very beneficial relationship. Everything is in order until a new factor is introduced.

As some of you may know, rhododendron, a flower popularly used in gardens, is not native to the UK. It was brought over in the mid-1700s from Spain and Portugal and cultivated here. It has adapted very well since then, and now there are few counties where rhododendron has not sprung up. Rhododendron currently enjoys popular use in various anti-arthritic potions and has a handful of other useful properties. However, it is displacing Largrass (native to both Europe and Australia). The issue is that the plant grows tall and thick enough to block out the sun for any plants stuck underneath it, reducing the amount of Largrass (and many other plants) that grows in an area. Because of this scarcity, pregnant Crups or Nifflers have begun to seek other sources to soothe their stomachs, including St. John’s wort and juniper. Unfortunately, these plants have abortifacient properties (they terminate pregnancies). This has resulted in lower birth rates of a handful of species in the wild, as well as among breeders. With lower rates of certain animals in the wild, the entire ecosystem gets a bit destabilized, causing headaches and serious concerns for potion-makers, creature handlers, and even the Ministry of Magic, as some animals may wander out into Muggle territory in search for food.

Additionally, invasive plants occasionally require more resources -- such as water -- than native ones, as they are not accustomed to the area. When alien plants take too much water, the ground can become too dry for other plants to survive and cause extinction or endangerment of another plant species. By changing the environment, flood and fire risks increase, which further damage the habitat. Fortunately, when growing in a greenhouse, we need not worry about these possible ramifications. However, it is each of our responsibilities to ensure that we do not allow an invasive or alien plant to accidentally take hold outside of the greenhouse via accidental seed distribution or a desire to have some in our gardens.

Aggressive Plants and Plans
Before we move on, we need to touch on aggressive plants. You will have heard me use the term before applied to some of the plants we have studied. A simple definition of an aggressive plant is one that spreads farther or faster than you intend. For example, if you planted strawberries in a fenced-off area of your garden, but next year, they spread to the opposite side of your yard and are growing amongst your ornamental shrubs, strawberries would be an example of an aggressive plant. For some, this is a good thing, as, often, aggressive plants take little effort to maintain. However, for others who are attempting to grow specific plants in specific areas -- much like we do -- it can be quite troublesome!

Again, there is nothing inherently wrong with aggressive plants, but they are definitely something any herbologist should be aware of, and something that often goes hand-in-hand with invasive plants. It is important to note that aggressive plants are not necessarily invasive or foreign. Many aggressive plants are simply voracious spreaders in their own native area. However, the reason we are talking about these two together is because if a plant survives in an area other than its own, and is able to displace other plant life (which is the definition of an invasive plant), they are automatically considered aggressive. Non-aggressive plants would simply die when introduced to foreign conditions and competition from strange plant species that normally wouldn’t exist in their area.

In order to keep aggressive and invasive plants under control, there are a number of techniques used. Some of the simplest methods are by weeding out the unwanted plants where they spring up, or by growing aggressive plants in pots so that their root systems cannot send out creepers to expand their range.¹ However, these are not the only ways to limit the area in which a plant can grow. If you are growing plants in conditions where it is impossible, undesirable, or inconvenient to separate them into smaller containers, the Containment Charm will do the trick. It can take a fair bit of concentration if your intended area is larger than a flowerpot, but fortunately the only backfire is the spell simply not working and the plant spreading to an area where it is not wanted, in which case, the undesired plant can be removed after the fact. You will need to concentrate on both the plant in question and the area you would like to relegate it to. Naturally, the larger the area, the trickier the spell is, so in most situations you’ll be using it in, the concentration will be on the lower end of the spectrum, as you will not be casting it on large plots or fields. The spell’s details are as follows.

There are also some potions available that can be applied to plants to keep them from growing. The Stunting Solution, for example, will keep a plant from propagating and reproducing, essentially killing it off for the next season. Of course, there are some drawbacks in that anything planted in soil that has been treated with the solution will be quite difficult to cultivate for the next few seasons.

Fierce Flowers and Hostile Herbs
Now that we have those definitions and warnings out of the way, I would like to set aside the last chunk of class to talk about a few plants that fall under these categories. As with many of the plants discussed in Year One, these plants are useful for younger students and novice herbologists as they are so easy to grow. Keep in mind that while they are not necessarily dangerous to grow, you need to be responsible for ensuring they do not become a problem!

Creeping Ivy
Hedera vagora is actually native to Europe and Asia, though it has been cultivated all over the world and has taken root quickly in all areas. It appears indistinguishable from common ivy, Hedera helix, until such time as it attempts to move of its own volition. It requires full shade and soil with a pH between 6.5 and 7.0. If your ivy is having a difficult time getting started, be sure to check the pH of your soil, as alkalinity can severely deter growth. While growing, water frequently to keep the soil moist, but once it has officially become established, there is very little you need to do to care for your plant. The vines will grow ever longer each year, though it usually takes up to the third year to see much growth (unless you have augmented the plant’s growth with charms or dragon dung), but after the third year it grows as fast as a rampaging hippogriff!

Creeping Ivy is the perfect example of an aggressive, and potentially invasive, herb. In fact, Creeping Ivy does not have to be introduced to a new area by humans or animals. It could travel to a new country all on its own! Of course, traveling that kind of distance would take decades, or potentially even hundreds of years. On the smaller scale of gardens or greenhouses, this plant can pose quite a problem, as it will actually make attempts to purposefully smother or take over the spots of other plants. On very rare occasions, it has attempted to crawl up children or small animals, but even a toddler can easily outrun the plant, and these cases have never ended in fatality. Fortunately, the Containment Charm does still work on this plant, though you will need to recast frequently. Additionally, if you start to see your Creeping Ivy wandering off, it is receptive to both the Stunning Spell, the Knockback Jinx, and the Impediment Jinx. If, for various reasons, you do not wish to jinx your own plants, Creeping Ivy can also be tempted back to its original location by adding large amounts of dragon dung to the desired area, at which time you can replace your Containment Charm. Additionally, it is a commonly-held belief that if you place Creeping Ivy in a place where it is prominently displayed (and one that meets all its growing requirements), it will not feel compelled to roam around or attack other plants to take their spot.

Creeping Ivy is often grown merely for ornamentation in magical households and gardens, but their leaves do have some useful properties. It is a main ingredient in the most popular forms of Bruise Removal Paste, and also enjoys some popularity in potions that treat ailments of the kidneys. Moreover, if you are a lover of teas, the leaves make an excellent blend that have the beneficial side effects of easing a persistent cough.

Lovage
While it is perhaps odd for a plant with such a sweet name to be so aggressive, this plant can thrive in nearly any conditions! Lovage, or Levisticum officinale, is not actually native to the United Kingdom, though it is certainly not an uncommon sight. The plant was originally native to the Mediterranean, particularly the Balkans, as well as France. However, due to being introduced in gardens and accidentally propagating elsewhere, it has spread throughout the country. As long as it has full sun (though, truthfully, if it has less than the ideal six hours, it will still grow) and soil with good drainage and a pH of roughly 6.5, you should have no problems! You can water this plant quite frequently, but as stated, be sure that the water can drain. Remember that if growing in the greenhouses at Hogwarts, you may use a Severing Charm to add drainage to any of our plots!

Lovage is only mildly aggressive when compared to Creeping Ivy. Simple weeding and/or a Containment Charm will easily do the trick. It can also be grown in a pot, but as this practice generally limits the size, it is not commonly done by those wishing to sell parts as potion ingredients. Speaking of ingredients, the roots, leaves, and even the seeds have assorted uses in potions and healing. Its roots are used in fever-reducing potions, such as Fever Reliever, and digestion aids. The leaves, on the other hand, are used in draughts that cause confusion, such as the Befuddling Brew and the Reckless Refreshment, ever popular among schoolchildren. Note: stems can also be used for this purpose, though only if they are a year old or younger. Finally, the seeds enjoy use in various eye drop solutions. While the plant does sport yellow flowers in the summer, they do not have any practical use that has been discovered.

Snakeweed
Also called bistort, dragonwort, and osterick among many other names, Polygonum bistorta is actually a relative of knotgrass. It blooms twice: once in early summer and once more in the fall, sprouting furry pinkish stalks. It can tolerate anything between full sun to partial shade, as it is not very picky, and while it does best in well-watered areas, it can survive droughts or lack of watering just fine. Additionally, the pH range it requires is quite large; you’ll have a hard time finding arable land with soil not to its liking. It can survive anywhere between 5.6 to 8.5. The one specific recommendation for this plant is to deadhead on a regular basis (if you do not remember this term, refer back to Lesson Three of this year), as this will promote another bloom in the same area, which is useful if you are collecting the flowers for potion or medicinal use.

Unlike lovage and Creeping Ivy, snakeweed is not technically invasive, though because it is so easy to care for, it can spread and run rampant through your garden if you do not take care to limit its area. As always, this can be done via planting it in a container, using a Containment Charm, or simply dealing with strays as they pop up. However, there is no need for more intense measures such as the Stunting Solution.

The flowers of this plant are one of its most viable parts, as they are used in stomach settling solutions and ulcer elixirs (interestingly, it seems to be able to both cause ulcers and treat them). The leaves, on the other hand, have fewer uses. They are popularly used in snakeweed tea, a favorite of my mother, as well as used in a delightful herb pudding. Its leaves (as well as its roots) are used as antidotes against poisons that cause internal bleeding. Interestingly, the roots are most often used powdered, while moisture is often extracted from the leaves and flowers and bottled to be used.

Closing
My, my! It looks like it’s time to bring another class to a close. I really could go on and on about invasive and aggressive plants -- both about the potential dangers they pose and the wonderful benefits they have -- but I don’t want to take over your day like an unruly patch of lovage! I’ll have to settle for seeing you next week. Before you leave, though, be sure to practice the Containment Charm on these Creeping Ivy seedlings! Please flag me down if you need help, though plants this young should pose little threat to you!

Footnotes

1. Plants like strawberries, bamboo, and wild ginger spread this way. These would be some excellent candidates for growing in pots if you did not want them to spread.

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