Guide to Caring for an Unknown Plant 1: Plant Type and Light

This article is the first in a series of four guides to be published in December, designed to help you decide how to care for a plant you know nothing about.

You’re on your way back from the plant store, an unplanned but pleasant detour after a day’s shopping. On a whim, you buy a plant you’ve never seen before, but which you really like. To make matters worse, it’s not identified by the store. So how do you know how to care for it?

Why Look for Information

In general, we like clear, unambiguous instructions. That’s why many have a regular plant maintenance schedule, often weekly, and don’t ask themselves any more questions. (They also lose far more plants to rot than those who dare to stick their finger in the soil).

However, basic advice has its limits, because houseplants are truly outdoor plants that survive our indoor conditions; they come to us just as much from the jungle as from the desert. I won’t surprise you by pointing out that the survival conditions of a tropical fern are quite different from those of a cactus!

To find the right information about a plant, serious sources (like this blog) are necessary… but it’s hard to find information without having the name of the new plant!

Purpose of These Guides

The care of houseplants is not a matter of arbitrary chance. On the contrary, there are many constants, provided you take the time to think about the plant you want to care for.

This series of “maintenance guides for an unknown plant” aims to encourage a more reflective approach to the care of our green friends. By observing a few external characteristics, we can come to understand the general care of a houseplant whose name escapes us.

What These Guides Are Not

This is not a basic guide to houseplant care. There are many other articles that will give neophytes all the advice they need to get started with this wonderful green passion! We won’t be talking about drainage layers or pots with holes in them.

Foreword

The first two guides deal with the light to give a plant, the third with watering, and the fourth with other aspects of caring for an unfamiliar plant (repotting, potting soil, fertilization, temperatures, propagation, etc.).

To illustrate the article’s objectives, we’ll take a look at this new mystery plant and, based on the information provided in the article, draw some conclusions that may help us understand its need for light.

Light: Some Basic Principles

It’s no coincidence that we’re focusing on light first: it’s the most important aspect of plant care. Indeed, all plants need a certain amount of light to survive, at varying levels.

Let’s start by remembering that light levels inside our homes are much lower than outside, and that we tend to think of our rooms as brighter than they are. In fact, almost all houseplants would love to have more light than they ever get in our homes. Just put them outside, in deep shade (when temperatures are right), and they’ll suddenly grow much faster and become much more beautiful.

More Frequent Damage

Secondly, although damage due to too much light is possible, it is mainly due to heat and lack of air circulation from a position too close to the window. Few plants suffer from direct sunlight. Read more in this article.

Finally, when you move a few inches away from a window, the concentration of light drops radically, so you really need to consider the light in the place where you’re placing the plant and not in a room in general.

The thing to remember about light and plants is that when in doubt, giving more light than too little is probably the safest option.

We sometimes hear the term “low-light plants” used. These plants are really plants that survive in low light, but would prefer more. And low light is not the absence of light!

For more information on brightness, see this article.

Plant Type: A Revealing Characteristic

The first thing to look for to understand a plant’s needs is its place in nature… which isn’t always easy.

Cacti

Identifying cacti is generally straightforward: their stems are swollen and generally leafless (or, alternatively, the leaves are succulent and disproportionate to the stems) or lined with spines (which are modified leaves). These adaptations enable cacti to withstand desert conditions.

In the case of an unknown cactus, it’s best to offer it as much light as possible, including plenty of direct sunlight.

Examples :  Echinocactus, Opuntia, Mammilaria, Echinopsis, Cereus

Miniature Trees

There are also many houseplants that, in the wild, become real trees or shrubs. One way of recognizing them is that their trunks are generally not very flexible, and become covered with bark as the weeks go by. Although the needs of trees used as houseplants vary enormously, it’s important to understand that they grow to large sizes in search of as much light as possible: they benefit from intense light, or at least bright light even without direct light (although many of those usually found in our interiors can make do with average light).

Examples: Ficus, Pachira, Dracaena, Schefflera, Codiaeum

Climbers

Climbing plants are pretty easy to identify: with age, their stems bend, but unlike drooping plants and groundcovers, they are also set with organs that enable them to climb, notably adventitious roots or tendrils. Climbing plants are a rather funny case: sometimes they climb only to avoid having to develop a solid trunk of their own, and sometimes to reach more light, but they live the early part of their lives in the shade. They can therefore be given bright light with a little direct sunlight, as well as more modest light.

Examples: Epipremnum, Philodendron hederaceum, Hedera helix, Monstera, Syngonium

Shade Plants

Finally, lowland plants… These plants form a less homogeneous category than the previous ones. We often see plants of restricted size, which tend to grow wider rather than taller, forming rosettes or multiplying by underground shoots, rhizomes or stolons. Their characteristic feature is that they grow in the shade of other plants and, unlike the preceding categories, develop no means of leaving this state: they humbly make do with what they have. These plants therefore tolerate bright to medium light (and sometimes even low light, if forced to do so).

Ex: Streptocarpus sect. Saintpaulia, Spathiphyllum, Begonia Rex

Informed readers will note that the above categories do not encapsulate the diversity that characterizes intercontinental flora. Indeed, they do! Other categories, such as succulents, vary so much in presentation and care that it would be pointless to name them. Fortunately, there’s another criterion that reveals a plant’s need for light, which we’ll look at in the next article.

Applied Example: The Mystery Plant

Based on the information we have about the type of plant, what can we say about its light requirements?

Observation suggests rosette growth (the plant produces very few stems and the petioles remain short overall). We can therefore conclude that bright light would be beneficial and medium light should be sufficient for it.

Practical Exercise

In the next article, we’ll talk about leaf color and its influence on a plant’s need for light. In the meantime, what can you tell us about the light requirements of the following unknown plants? Feel free to write your answers in the comments. Answers will appear in the next article.