Sometimes nature just isn’t good enough and you need to create fantastic flora to tempt, aid, or destroy your characters. With all the information provided to date, this installment of the column should help you create plants, and trees that--while impossible to exist on current Earth--are made believable in context.

Creating New Plant Life

1. What are you going for?

You already have an idea of what you want—a blood-red oak on the top of a mountain, a giant alien vine with flowerheads that vaguely resemble mouths, a giggle patch of daisies that tell riddles all day. Figure out what exactly the plant is going to be used for in the campaign.

• The plant is a monster/threat that must be vanquished or avoided.
• The plant is a conveyance to another place or holds an object. In this case, there’s nothing unusual about the plant, except maybe for size in terms of secret doorways. Carry on.
• The plant causes an effect, good or bad
• The plant furthers the plot (tells the future, explains a mystery, etc.)

2. Does its purpose require intelligence?

If the plant is only being used as a conveyance, to hold an object, or cause an effect, you probably won’t need to add any sentience to the plant. Some plant threats also will not need any intelligent action behind them. If the plant is a monster or is used to communicate information, however, you have to consider how the plant thinks.

For everything from walking trees to grabbing vines, there’s got to be mechanism running it. Although Venus flytraps and gourd vines use tactile sensitivity to react to a situation, a plant that actively goes for prey must have at least a rudimentary brain and nervous system to make it go. The innermost core of a stem can readily house a network of synapses, and the brain, or even just a node of networked lines could sit in the crown of roots or near the ovary of the flowerhead. Perhaps giant trees don’t have brains so much as a storage area of information collected over the years, one they could draw on readily. Sentient creatures such as Ents and plantlike races require complex brains and likely a brain stem for synapses to fire across.

Most brains we know feed off glucose to work. A plant’s sap—filled with the products of photosynthesis, water, and gases—would work nicely in producing a brain-happy environment, regardless of size. Age would be a big factor; most vines are annuals and only live a year at most. An annual or biennial such as this would probably only have instinctive reactions rather than actual thought. To produce a higher-functioning brain, more nutrients are needed over a longer period of time. A long-lived carnivorous vine with a working digestive tract would think and learn better than a rose bush that can only consume a little blood from stomas on its thorns.

In most games, it is probably best to keep intelligence to a minimum for practicality’s sake: Grab and stuff in maw, aim club-like seed pellet at object causing vibrations, duck and cover from danger. The higher the intelligence the more stacked the capabilities, but the larger the brain necessary to keep the creature functioning. Therefore, increased cognitive development should result in more capabilities as seen below, but there is an increased risk of damage and human-like behavior, which is fatal.

Another possibility would be duorganisms (thanks Eric E.!). Essentially an animal symbiote would attach itself to a plant, move inside, and eventually become a brain, with long tendrils (nervous system) moving through the tubes within the heartwood. This would more readily explain these cases of cognitive development in plants and keep it easy for the gamemaster over a number of settings.

3. Does the plant move?

Movement requires a mechanism guiding it, whether reactive or proactive. Plants that snap shut, instantly wrap, or explode on contact do not need functioning nervous systems—they are reactive. These are based on fact: some vines can actually be seen wrapping themselves around supports without using time-lapse photography. Called “circumnutation,” twining is achieved through a tendril which, once stimulated through sensitive spaces in the cell wall, increase growth in one side of the tendril and decreases in the other, causing a screw-like action. Man-tackling vines would have to be large and flexible, which would require a large water supply. Other plants such as Venus flytraps or sensitive plants can be used as traps to keep the characters busy.

Plants that choose to move to defend themselves, chase after prey, or reach for objects must have at the least rudimentary cognitive ability. Not only that but these creatures would require softwood interiors with flexible exteriors. There are two types of mobility in sentient plants. There are those that can move their stems and aerial tops but remain rooted, and those that can actually move their entire bodies from one place to another. Popular culture loves plants that can maneuver, including tangler trees in Piers Anthony’s Xanth series, Ents in Tolkien’s world, the Whomping Willow in the Harry Potter books, and man-grabbing vines in Jumanji and Raimi’s Evil Dead movies.

Another possibility is to make sentient plant-like creatures with botanical and animal components, such as bark-like skin and the ability to photosynthesize, but animal-based insides with muscles, blood flow, and a fully working nervous system. Otherwise the tree would require a softwood or woody vine interior with flexible bark. Regardless of the mechanics involved, such mobile plants would require nutrient-laden soil (when at rest) and plenty of water to stay flexible.

4. Does the plant communicate?

There are four types of communication that are relatively easy to use. The first is advantageous speaking; the plant will only be able to speak if there is sufficient wind passing through its limbs, hollows, or openings. To make annunciation clearer, a set of fibers or softwood cords can change the pitch, with osmosis tightening or relaxing each “string.” When there is no wind, however, the trees or plants would be silent.

The second form is true speech, as seen from the apple trees in the Wonderful Wizard of Oz. Several species of plants have air bladders, used to keep them afloat of expel seeds. Most plants have vacuoles, or empty spaces, within their cells and we could expand these to create a type of lungs that can sit within the stem or trunk of the plant. A plant using vacuoles or air bladders would use up most of it in a single sentence and have to wait for a time to obtain more. An intelligent tree could have several large air bladders to hold a whole conversation, filling one while using another to talk. Since all plants have vacuoles, this mechanism could be used to explain the mandrake’s scream and give voice to the smallest of plants.

The third type of communication is in the form of telepathy. This would require either a fully capable brain on the part of the plant, or an affinity on the part of the other party. Since this is already reaching heavy supernatural aspects, there is no mechanism to explain. It is likely that a plant with such a developed brain would be older in nature, having spent several years learning to communicate.

The fourth way would be using movement, limbs beating out specific beats or random actions from the plant that make it seem agreeable or threatening. The communication may be primitive, but this does not mean the creature itself has low intelligence.

5. Can the plant do some serious physical hurt?

Real plants are nifty. Touch-me-nots will explode on contact, shooting seeds far and wide. The exploding cucumber vine has enough force behind its seeds to shoot them up to twenty feet away. The dorian is the world’s only near-fatal fruit—this large spiked fruit has been documented as causing injuries in India when it falls on someone. Combine the possibilities and magic plants are downright dangerous.

Projectile-throwing plants are popular choices, spewing or flinging fruit weighing several pounds, or shooting dartlike poison needles via an air bladder mechanism. Good aim despite a lack of vision can be explained away by vibrations sensed underground of the person approaching. Jumanji had poison dart-throwing vines to paralyze prey before dragging the bodies into its maw.

Other plants, specifically trees, could heave their limbs around to club opponents to death. Again, without eyes, the tree would have to rely on their sensitivity to vibrations or perhaps to heat sources. The Whomping Willow from Harry Potter was a definite smacker. Add some long thorns to tree limbs and thin branches and even attacks from shrubs can get messy. Figure the tree may be a little clumsy and easy to confuse, but damage is spectacular when it does hit.

The burning bush of the Bible definitely caused quite a stir, and in nature it has already been done. Some plants, especially aromatic shrubs, are filled with volatile oils, alcohol included. Balloonflowers are particularly well known in some areas; the flowers swell just before opening and the gas inside can be ignited to send out a blue flame detectable in the dark. Other plants have highly flammable outer shells that burn off quickly and prevent forest fires from damaging the more vital parts. Fire-prone or even self-ignitable plants, trees, and bushes could kill off a character party with little or no extra work.

6. Does the Plant Cause a Magical Effect, Good or Bad?

Previous columns ran through a list of legends and myths involving plants cause good luck, love, or scaring off demons, but sometimes you just need a plant that does the work immediately. Forget the garlic when you can create a fungus that simply cures vampirism. Eat a bit of this seaweed and grow gills for an hour or two. Any effect you need is available in some sort of plant life.

7. Is the Plant unusual in Shape or Color?

This is where Google or Wikipedia is your friend, since they have just about every bit of strange plant marked down somewhere for you to crib off of. Need a giant tree looming up out of the sea? Look up “Salt-tolerant trees” and check out the mangrove. Want an entirely red plant to stick out in a snow-covered area? Look up “red bark” and check out the Gumbo Limbo tree with its gorgeous sunburned look. Whatever your idea, check through and see if you can come up with a how or why, even for the things that are WAY out there. If you want a tree of gold leaves (real gold), it may be easier to go the “divine intervention” route instead of the “tree somehow absorbs toxic metals” route, but at least you have an origin for that one annoying player that starts questioning its validity in the middle of a session.

Next up: That One Lost Article on Wetland/Water Plants.