Guide to Caring for an Unknown Plant 4: Other Aspects

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?

This article is a continuation of the other guides to caring for an unknown plant:

1. Plant type and light
2. Leaf color and light
3. The question of watering

Foreword

Plant care is primarily concerned with light and watering requirements. Other considerations, such as potting, potting soil, fertilizers and temperatures, are much less central. With the good habits already acquired as part of routine plant care, there are few major mistakes you can make.

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

Answers to the Practical Exercise (Guide 3)

1) The leaves are fleshy and tomentose, the stems are thick and the plant is clearly succulent. It should be watered when the soil has dried out thoroughly.

Plant name: Kalanchoe tomentosa.

2) Leaves are slightly fleshy and inflexible. Stalks are slightly thick. It can be watered when the soil starts to dry out.

Plant name:Peperomia capareta (Incidentally, its small root system and knowledge of plant identification remind us that some peperomias are epiphytes: it’s easy to cause root rot by overwatering them)

3) Leaves are thin and flexible. No apparent water-holding organs. Water when the potting soil starts to dry out, but observe intensively for the first few weeks: it may be necessary to keep the potting soil slightly moist at all times.

Plant name : Hibiscus variegata

Now let’s look at other aspects of plant care:

Potting Soil

A separate article on potting soils will follow shortly. To keep things simple, “houseplant” potting soils are suitable in most cases. A lighter potting soil, such as that for cacti and succulents, is preferred by said cacti and succulents, as well as for epiphytic plants and plants that don’t need to be watered frequently. As for the need for acidic potting soil for certain plants, there’s really no way of knowing until you’ve properly identified the plant, but this is rarely a sine qua non.

Repotting

Repotting is not often a matter of life and death for plants. The following general rules apply:

• Cacti and succulents prefer to be more cramped (to avoid staying in excessively damp soil and rotting);
• Climbing and epiphytic plants can also be cramped, as they do not develop extensive root systems. When repotting epiphytic plants, it’s important to be careful with their delicate roots, and to give them as little rough treatment as possible;
• Fast-growing plants need to be repotted more often;
• Plants whose growth you want to slow down should not be repotted, but rather resurfaced (see the article When You Can’t Repot, Top-Dress).

For more information, here’s a guide on how to repot a houseplant.

And to know when to do it, here are the signs it’s time to repot your houseplant.

Fertilization

As a general rule, fast-growing plants need more fertilizer than slow-growing ones. Plants from poor soils, such as cacti and epiphytes, need less fertilization. In any case, it’s best to use fertilizer sparingly. Plants that have just been bought rarely need fertilizing (they are fertilized by the seller), and neither do those that have just been repotted (commercial potting soils often contain fertilizer).

Lastly, we only fertilize during the growing season, which depends on the plants’ country of origin… while it’s not easy to know your plant’s country of origin, it’s much easier to know the growing season, fortunately!

Temperatures

It’s really the plant’s origin, i.e. the climate of its natural habitat, that determines the temperatures it can withstand. It’s therefore very difficult to know the limits of a plant without having identified it. When in doubt, a stable temperature of between 18 and 24°C (64-75?) – as found in our homes – is perhaps the safest.

Propagation

Some plants have obvious ways of multiplying, such as stolons (Saxifraga, Chlorophytum comosum) or babies (orchid keikis, Haworthia offshoots). Otherwise, most plants can be propagated by stem cuttings, especially climbers, which are often the easiest to reproduce. Of course, some also multiply by a single leaf (Peperomia, Saintpaulia, Echeverria and many other succulents), but there’s no way of knowing this by observation alone.

Finally, not all plants are easy to propagate under normal living conditions. Some require a certain amount of warmth, and most benefit from increased humidity during the rooting period. So, when it comes to propagation, a certain amount of “trial and error” prevails.

Toxicity

Nor is there any way of knowing whether a plant is toxic or not, and even for known plants, you have to be very careful, as there can be errors on the lists or in the searches. What’s more, most of the information is only relevant to humans, dogs and cats, but not to other animals. Safety is a must!

Applied Example: The Mystery Plant

Here’s a summary of everything we can learn about this plant by observing it, even if we don’t know its name.

• Light: rosette-shaped, rather low-growing, suggesting a lowland plant. With its two-tone green leaves, it will survive in medium light, but would prefer bright light without direct sun to make flowers.
• Watering: with its slightly leathery leaves and thick petioles, it can be watered when the potting soil starts to dry out. In the first few months, it’s best to observe whether the stems drop rapidly and adjust watering accordingly.
• Humidity: the mystery plant prefers higher humidity, but adapts to the humidity usually found in the home.
• Potting: nothing special.
• Soil: nothing special.
• Fertilization: we don’t yet know whether it grows fast or slowly. To be on the safe side, a gentle fertilization could be started about six months after acquisition, as long as the plant is in its growing period.
• Temperatures: in the absence of information, the safest thing to do is to keep it at room temperature (16-24°C, 64-75?) at all times.
• Toxicity: caution is advised as we have no information on this subject.

Corrections

Now that I’ve written the article, I can confess something: the name of the plant wasn’t unfamiliar to me. In fact, it’s Primulina dryas ‘Hisako’ (sold under the name Streptocarpus ‘Pretty Turtle’), a plant in the Gesneriaceae family, very similar in cultivation to African violets (Saintpaulia – which, by the way, can be recognized in the plant by the shape of the leaves and the rosette growth pattern). I was therefore able to research and correct certain aspects.

	My hypothesis	Correction
Light	Bright light for flowers, tolerates medium light.	Bright light is recommended.
Watering	When the soil starts to dry out.	Ditto; the plant recovers well from brief droughts.
Humidity	Benefits from increased humidity, but tolerates house humidity.	Same.
Potting	No special features.	Same.
Potting soil	No special features.	Ditto. You’d think it would need a special soil, like African violets, but that’s not the case.
Fertilizers	Gentle fertilization to start with	A quarter or even an eighth of the recommended dose is recommended.
Temperatures	16-24 °C, 64-75?	The plant tolerates a drop in temperature of up to 10°C, 50?.
Toxicity	Caution	The plant is not toxic.
Special care	–	As with African violets, foliage is prone to leaf spot if wet, so careful watering or watering from below is recommended.

Well, that wasn’t so bad!

Conclusion

As we can see from the example chosen for this series of guides, a lot can be deduced from the judicious observation of an unknown plant whose name we don’t know. In fact, most of the final considerations were not wrong: the research only enabled us to clarify certain aspects, such as temperature or fertilization. And the most important aspects – light and watering requirements (guides 1 to 3) – are fairly easy to deduce from the type of plant, the color of its leaves and its degree of succulence.

The scenario presented in the introduction to this article – the impulse purchase of an unidentified plant – is probably not unfamiliar to readers of this blog. Indeed, it would be a bold statement to assert that plants are always well identified in stores, let alone cultivars! Every gardener benefits from developing a more reflective approach to looking after their green friends. Yes, even laidback gardeners!