Philodendron Atom (Complete Care & PROPAGATION #1 Guide!)

ruffled leaves of the rare Philodendron Atom, a low-growing dwarf cultivar of a philodendron selloum (tree philodendron).

The rare Philodendron Atom is a small indoor plant with glossy green leaves. Leaves grow low and are lightly ruffled, giving this evergreen Philodendron a bushy look. 🙂

Low-maintenance and undemanding, the Philodendron Atom can tolerate low-light conditions though it does best in bright, indirect light, plenty of water during the growing season, and high humidity (at least >50%, with 70% being ideal).

Monthly application of balanced fertilizer at half strength helps speed up the Philodendron Atom’s growth.

We’ll show you everything you need to know to help your Philodendron Atom thrive. They are beginner-friendly, so you have nothing to worry about!

Origins

A relatively new plant, there’s not a lot of information on the Philodendron Atom.

We know it is a dwarf cultivar of the Philodendron Selloum (scientific name: Philodendron Selloum ‘Atom’) that was recently reclassified to Thaumatophyllum Selloum ‘Atom’.

Both are native to the rainforests of Brazil and Paraguay.

Philodendron Atom or Philodendron Super Atom??

Just a quick word on the confusion surrounding the atom vs. super atom.

The Philodendron Atom is sometimes referred to as the “super atom” instead of the atom. Some articles claim that the super atom is the smaller version of the atom, but we haven’t found any evidence of this.

It seems that both names refer to the same Atom plant.

Caring for your Philodendron Atom

Light

The Philodendron Atom is a plant that can tolerate low light. However, for best growth, ample amounts (at least 6 hours) of bright, indirect light is ideal. East or West-facing windows are a good choice.

Having said that, ours is growing fine when placed on our office desk, in a bright room with indirect light.

a potted philodendron atom
The Philodendron Selloum ‘Atom’ is the dwarf cultivar of the Philodendron Selloum.
Copyright © 2022 hmflowers (Hallmark Flowers & Gifts). All Rights Reserved. Used with Permission.

Water

Watering is an important part of care for your Philodendron Atom. Here are our watering tips:

  • ALWAYS check the soil’s moisture with your finger before watering. If the soil feels slightly damp, wait and check back again in a day or two. Only when the topsoil is dry should you water your plant.
  • Water near the soil level, and avoid wetting its leaves.
  • When watering, water deeply, until excess water runs out of the drainage hole. Empty the saucer so that your plant is never sitting in a stagnant pool of water.
  • You’ll notice that the Philodendron Atom needs more frequent watering during the spring and summer months, when evaporation rates are higher and when it is actively growing.
  • Your Philodendron Atom is susceptible to overwatering. If in doubt, err on the side of underwatering.

It’s important to casually observe your plant so that it can give you “feedback” on your watering practices. An overwatered Philodendron Atom will have yellow leaves, and soft, droopy stems.

On the other hand, crispy leaves with cakey soil indicates an underwatered plant.

Humidity

Humidity-wise, the higher the better! Aim for >50% minimally, with 70% being ideal. This tropical plant is used to living in the rainforest, where high levels of rainfall and density of plants and vegetation contributes to very high moisture levels in the air.

We like using a humidifier to give our tropical indoor plants a boost.

topview of a philodendron atom with waxy green leaves
Copyright © 2022 hmflowers (Hallmark Flowers & Gifts). All Rights Reserved. Used with Permission.

Temperature

Made for mild indoor environments, keep temperatures between 65 – 85 degrees F (18 – 29 degrees C) for healthy growth. Dips below 55 degrees F (13 degrees C) will harm your Philodendron Atom, as they are not cold-hardy.

Also, make sure your little Atom is in a spot out of the way of air vents or drafty doors. Anything that creates temperature fluctuations or cold chills should be avoided – your Philodendron Atom may start dropping leaves otherwise!

Flowering

Your Philodendron Atom rarely flowers when kept indoors away from its natural habitat. However, if you’re very lucky, you may spot an inflorescence that consists of a spadix and a cream-purple spathe in a mature plant.

The spathe is a modified leaf that has a boat-like shape, protecting the central spadix, which is like a long spike. Along the spadix grow tiny and numerous flowers.

Truth be told, Philodendron Atoms are not sought-after for their flowers. Instead, they are grown for their lush green foliage.

Growth

Your upright-growing, compact plant is made for growing indoors. It is relatively slow-growing, however when fully mature reaches a height and width of about 8 – 12 inches (20 – 30cm).

When young, leaves are small and whole, before branching out in thick lobes, and developing wavy leaf edges and curled leaves. When mature, they look at lot more like the Philodendron Selloum. 🙂

Soil or Growing Medium

When growing your Philodendron Atom, we like using a chunky, well-draining mix that still holds a little moisture. Our favorite mixture for the Atom is:

Perlite and orchid bark help lighen the potting mix and improve drainage qualities. Using a high-quality indoor potting mix is key!

a philodendron atom, a small bushy plant with thick stems and leaves
Copyright © 2022 hmflowers (Hallmark Flowers & Gifts). All Rights Reserved. Used with Permission.

Fertilizer

In terms of fertilizing, your Philodendron Atom is not fussy. Any liquid houseplant fertilizer is adequate. We like using Dyna-Gro Grow, which is gentle and nutritionally complete. It also has high amounts of nitrogen to encourage leafy growth for heavily-foliaged plants.

Apply liquid fertilizer once a month during the active growing season (spring and summer months), at half-strength.

Hold off fertilizing during the fall and winter. Less is better in this case.

If you see a thin white crust forming on the soil line, this means that your plant is overfertilized. You’ll need to flush out the fertilizer salts by allowing water to run through the soil for a few minutes. We like taking our plant to the bathtub and running room temperature water through the plant until the salts run off.

Repotting

Repotting is not a frequent occurrence for your Philodendron Atom, as it is a small and slow-growing plant.

On average, expect to repot once every 2-3 years, during the spring time which is the start of the growing season. This gives your plant time to establish itself in its new pot during the summer months when growth is at its highest.

You’ll know your Philodendron Atom needs repotting when you spot any signs of your plant becoming root-bound.

  • Symptoms of a root-bound plant are similar to that of an underwatered plant. The plant grows much more slowly than usual and has cripsy brown or yellow leaves.
  • Your plant appears as if it never has enough to drink, no matter how much you water it. Additionally, water takes a long time to drain through the plant. This points to a very densely-packed pot. (In severe cases however, water drains through immediately without being absorbed.)
  • Your plant has little roots emerging from the bottom of the drainage hole or has roots appearing above the soil.
  • In extreme cases, your container may be warped due to the pressure of the tightly-squeezed roots pressing against the container. (Of course, this is only applicable if you are using a flimsy plastic container. You’ve also likely held off repotting for several years by this time!)

Toxicity

Unfortunately, your Philodendron Atom is toxic to animals and humans when ingested. This is due to the presence of calcium oxalate crystals, that pierce skin tissues and cause nausea and vomiting.

If you’re after a pet and child-friendly plant, try a Majesty Palm, Hoya, Calathea or Peperomia.

Propagation

Stem cuttings are the easiest way to propagate your Philodendron Atom.

We prefer using water propagation so that you can observe healthy root development before replanting into a permanent potting mix.

The best time to propagate your plant is during spring. The warm, humid conditions and when your plant is actively growing increases the chances of successful propagation.

Here’s how:

  1. Choose a healthy portion of the stem that has at least 2-3 nodes.
  2. Using clean garden shears, cut off the identified part below the node.
  3. Remove any leaves from the bottom half of the stem cutting (as this will be submerged in water).
  4. Add room temperature water into a jar.
  5. Place your stem cutting into the water jar, ensuring that no leaves are submerged. At least one node should be submerged.
  6. Place your stem cutting in a warm and humid location, with plenty of indirect light (but no direct sunlight). If you have a humidifier, place it next to the jar and set it at 75%.
  7. Replace the water every few days to prevent it from turning murky.
  8. In 2-3 weeks, you should see roots starting to grow.
  9. Once roots grow to 2 inches (5 cm) long, you can replant them in their permanent home.
  10. Prepare a pot (with drainage holes) with fresh soil and plant your stem cutting into the pot.
  11. Treat as you would any other Philodendron Atom.

Pruning

You don’t need to prune your Philodendron Atom unless you see a diseased or pest-infected part of the leaf.

Pruning close to the crown can damage sensitive tissue and may even cause harm. Furthermore, cutting back too much can leave the plant denuded (bare) for a long time due to its slow growth habit.

The best solution? Just leave it be. Let yellowing or dead leaves fall off naturally. Yes, if your plant is diseased, definitely prune it, but limit the pruning to the affected area only.

close up of thick stems of a philodendron atom
Copyright © 2022 hmflowers (Hallmark Flowers & Gifts). All Rights Reserved. Used with Permission.

You may also want to deadhead the spathes (inflorescence), which won’t harm the plant. This is so that the plant can focus its energy elsewhere, such as growing that lush foliage!

Common Pests and Diseases

Root Rot

As with many Philodendrons, your Philodendron Atom is susceptible to overwatering and root rot. Root rot happens when your plant is so overwatered that its roots cannot breathe and start to decay. Moisture-loving fungi may also feed on rotting roots.

The best way to deal with root rot is to prevent it altogether. Our top tips:

  • Make sure you only water your plant when the topsoil is dry.
  • Use a pot with drainage holes.
  • Choose a planter that is an appropriate size for the plant. A too-big pot can lead to overwatering.
  • Empty your plant’s saucer after watering.
  • Use a well-draining potting mix. The particular blend depends on your plant and what kind of soil it is used to in its native environment. See Soil section for details.

However, if its too late – here’s how to save your overwatered plant.

Spider Mites, Mealybugs, Fungus Gnats, Scale, Aphids

Houseplant pests rarely originate in the home, rather are often introduced into the house by an infected plant. For this reason, it’s good practice to inspect your plant for pests before bringing it home and at regular intervals after that.

You can also choose to apply a dilute solution of neem oil as a preventative measure to ward off pests. But, the best way to reduce the risk of infections is to keep your plants healthy! 🙂

Here’s what to look out for:

  • Aphids – these are light green and pear-shaped, about 1/8 of an inch (0.3cm) long. However, there are over 5,000 species of aphids that also come in black, pink, and white.
  • Spider mites – they are about 1/50 inch (0.5mm) in size, so it’s not easy to observe them directly without a microscope. Instead, look out for pale, grey stipplings on leaves or fine webbing on leaf undersides and near the stems as signs of an infestation.
  • Mealybugs – these sap-suckers look like little bits of cotton wool. While easily recognizable, they like to cluster together in hard-to-reach corners of the plant.
  • Fungus Gnats – attracted to overwatered plants, fungus gnats are black flying insects, usually around 1/8 inch (0.3cm) long, and look like fruit flies.
  • Scale – scale often look like immobile shell-like bumps that are clustered together, usually between 1/16 (0.2cm) to 1/8 inch (0.3cm) long. They come in many colors.

We recommend the Bonide Insecticidal Soap Spray to kill houseplant pests. Insecticidal soap penetrates exoskeletons and dries out cells. We keep it on deck in case of pest emergencies – it is also convenient to tackle all these pests in one product!

Troubleshooting

Yellow Leaves

Yellow leaves are usually a sign of overwatering. Adjust your watering practices accordingly. if your plant is chronically overwatered, you may need to take more drastic steps.

Here’s our step-by-step guide on how to save your overwatered plant.

Dropping Leaves

Too dry air (low humidity) and cold chills can cause leaf drop. A severely overwatered plant can also cause dropping leaves.

FAQ

What’s the difference between Philodendron Selloum and Philodendron Atom?

When comparing the two, the Philodendron Selloum has long, finger-like lobes that run on either side of its midribs.

The Atom, its dwarf cultivar, is much smaller in size. Plus, its leaves are small and bunched together with much thicker lobes than the Tree Philodendron.

Where can I buy a Philodendron Atom?

We bought our Philodendron Atom from Etsy. Being a rare cultivar, it will be hard to find at physical stores, so looking online is your best bet.

Other compact, upright-growing plants

Other Philodendrons we Love

Wrapping Up

Your Philodendron Atom is an adorable bushy plant with wavy, thick lobed leaves. For best growth,

  • Provide it with bright, indirect light.
  • A well-draining potting mix is key.
  • Water when the topsoil is dry, noting that water requirements drop dramatically in fall and winter.
  • Be careful not to overwater – they are susceptible to root rot.
  • Keep it indoors, with humidity >50%.
  • Lightly fertilize with liquid houseplant fertilizer, monthly during the growing season at half-strength.
Deborah

Deborah is a plant enthusiast and founder of Gardening Collective.