Leaf Language - A Guide To Understanding Your Plants

Green tropical foliage close-up

lan·guage

1. the system of communication used by a particular community.

Millions and million and millions of years ago, algae decided it was bored being single-celled and slimy and decided to try being terrestrial and leafy green. This process was very long, complex and some crazy science was involved.

But I like to think of it differently.

I like to imagine the evolution of plants as one big cheerleading routine; the Cambrian algae cheering on the Ordovician spores, the Devonian bacteria laying the foundation for the Carboniferous boom, the Jurassic warmth pushing for the Cenozoic finale of flowers and fruits. All these moving parts communicating to each other to ensure the success of the other.

Flora and fauna have been communicating with each other since their very beginning, through a vast network of underground connections, complex chemical signals, and innate biological urges. If you don’t believe me, brush up on your Peter Wohlleben.

Since our species more or less claimed ownership of Earth and all her bounty, plants have had to find a way to express their needs to us, or rather - in order to support their survival, we have had to learn their language. They do this largely through parts of their systems that we can see - their leaves.

Various leaves: fern, oak, ivy, cedar

I hear this all the time, “I just don’t know what my plant WANTS!” I will endeavour to explain how I study the leaves of my plants in order to understand what they want and, hopefully after reading this, you and your plants can begin a relationship built of communication, not resentment.

If you have attended my Plant Care 101 class, you know how passionate I am about checking in on your plants. If you take the time, say once a week, to really tune in, you will begin to notice patterns indicative of their needs, not to mention being able to jump on a pest infestation BEFORE it takes over your house!

MOISTURE

Brown and crispy = “I need more water.” Sometimes this means MORE water rather than water more often. Tossing the last of your morning 8 ounces doesn’t cut it. Water evenly, deeply and less often.

Crispy edges = “I need more humidity.” Often in the winter when our fireplaces and heaters are cranked, our plants suffer from this dry heat. Supplements with misting daily, buy a humidifier or group plants together (plants produce small amounts of their own humidity).

Drooping, misshapen, yellow edges, falling off = ‘You’re watering me too much.” Always push your finger deep into the soil to check for sogginess near the roots. If the soil is clogged with water, oxygen is unable to move through the plant’s cells and it will begin to rot, forcing the leaves to droop and drop.

Dried palm leaf

LIGHT

Brown crispy spots = “I’m burning!” Too much direct sunlight can burn most houseplants. In the dead of summer or if you have your plants outside for a summer vay-cay, move them into a gentle indirect light.

Pale, sparse and leaning one way = “I need more light.” Sometimes this is unavoidable. We all suffer slightly during the PNW dark winter days. If you can, position your plants by a bright window. Don’t worry too much, they will bounce back when the sun returns.

Pilea Pepperomoides in terra cotta pot

NUTRIENTS

Unusually pale = ‘I’m hungry!” Give them some organic water-soluble fertilizer once every two weeks in the spring and summer. If it is a fruiting/flowering plant you may need to feed more often.

Stunted growth and lead discolouration = “I need vitamins.” Observed more often in outdoor gardens, nutrient deficiencies are complex and diagnoses can cause headaches. I found this chart very helpful.

Mircro nutrient deficiencies in plants shown on leaves.

Yellow spots = “You’re feeding me too much.” Over-fertilizing causes a build up of solids in the soil. This reduces the amount of water a plant can absorb and causes the plant to ‘burn’ as the leaves don’t have enough water to cool them.

PESTS & DISEASE

I’ll save the specifics for another day, but if you see signs of insects or disease on the leaves, stems and soil, immediately quarantine the plant and treat accordingly.

Did I cover everything? I encourage you to ask questions in the comments below, or reach out to me through my socials!