The beautiful, usually upward-pointing, slender, elongated bright green leaves with a paler, thick midrib make Philodendron crassinervium (pronounced cras-SEE-nervium) a unique houseplant. Did you know that the swollen midrib helps it store water for use in drier seasons?
This rare aroid native to South and Southern East Brazil will give your home a unique tropical vibe. Also, it is easy to care for, with needs much or less than what most other Philodendrons require.
How do you care for your Philodendron crassinervium, how much does it cost, and where can you buy it? We have answers to all these questions, plus how it differs from philodendron alternans.
However, before you buy it, you must know it is somewhat (mildly to moderately) toxic to pets like dogs and cats or your kids. Why? Because it has insoluble calcium oxalates like the rest of the aroids, including Pothos, Monsteras, Alocasia, or Rhaphidophora plants.
About Philodendron crassinervium
Philodendron crassinervium (Lindl.) was first published by a British botanist John Lindley (1799-1865), in 1837. It is an accepted Philodendron species native to South and Southeastern Brazil, from Minas Gerais state, north of Rio de Janeiro, to Santa Catarina.
The name crassinervium comes from the Latin words Crassus denoting plump, and nervium or nervis, meaning nerve. The name describes the unusually plumb or swollen and conspicuous midrib.
This plant belongs to the Araceae (aroids) family and Philodendron section Baursia. Plants in this section have obscure primary lateral veins on their leaves. Also, most members of this section have oblong to elongated oblong leaves. However, some show lots of variation in leaf shape and sexual features, including inflorescences.
Contrary to what many people assume, Philodendron lanceolatum (Schott) is a synonym of Philodendron crassinervium. However, its close lookalike, Philodendron alternans (Schott), is a distinct, accepted species.
1. Growing habits, size, and growth rate
Philodendron crassinervium grows both as an epiphyte and as a terrestrial creeper. Also, it is common to find it growing over rocks. It occurs in tropical biomes that dry seasonally, especially in moist subtropical rainforests and tropical coastlines, 935 to 4,100 feet (100 -1,250 m) above sea level.
Crassinervium growth rate is relatively slow and will hardly go beyond 4 feet when creeping on the ground. However, if you give and train it on a moss pole a place to climb, it can grow much taller, going several feet high.
2. How to identify Philodendron crassinervium
We will look at leaves and stems to help you identify this adorable aroid easily. Also, we will mention something small on flowers, which you are unlikely to see under cultivation.
Please, note that this species is highly variable. Therefore, you may notice some differences from one specimen to another.
1. Stems
Philodendron crassinervium will have smooth repent (rhizomatous ) or scandent (climbing) green stems. These stems are thin (up to 0.8 inches in diameter) and internodes are 2.8-4 inches long.
If allowed to climb, the aerial roots will be red to reddish-brown as they emergy but will turn dark brown as they harden and age.
Lastly, the stems will have light-yellow greenish cataphylls, 3-8 inches long. These bracts may be unribbed or single-ribbed; as they age, they get twisted backward. Also, note that the cataphylls are deciduous. However, initially persist but will fall by the time the leaf blade matures.
2. Leaves
Philodendron crassinervium will have bright green, sometimes medium to dark green narrow, elongated (linear-oblong to lance-shaped oblong) leaves. Their apex is cuspidate-acuminate, and they have narrowly cuneate bases.
These leaves usually point upwards, grow nearly 3 feet long, and are up to 4 inches wide, but some specimens may have shorter broader leaves.
Furthermore, this aroid will have sub-leathery to moderately leathery that are semi-glossy on the upper side, while the lower is moderately matte and paler.
One unique thing about these leaves is the midrib. Crassinervium has a thick (about 0.4 inches at the base) paler midrib that strongly attenuates towards the apex and obscure lateral veins. These swollen, spongy, when touched midrib, stores water for use in dry spells.
Also, the midrib has reddish glands on either side that produce a clear sap that gives the leaves a freckled look.
Lastly,crassinervium has subterete, green petioles that are 3.9-5 inches long and sheathed up to 1.2 inches from the base. Also, they may be reddish or purplish-tinged, especially towards the apex.
3. Flowers
As already mentioned, crassinervium plants don’t usually flower under cultivation. However, if they do, they will have inflorescences with a stipitate spadix and a boat-shaped spathe divided into a tube and blade. The spathe is green on the outside, while the inner side is purple on the tube side and pale green on the blade.
Philodendron crassinervium vs Philodendron alternans
These two plants bear striking resemblance; some people assume they are synonyms. However, each is a unique species.
Philodendron alternans grow mainly as an epiphyte, while crassinervium is repent or a low climber. Also, its leaves are narrower and much longer with less conspicuous or thinner midrib than crassinervium.
The other difference is that while P. crassinervium leaf blades point upward; alternans leaves are usually pendent with upright-turned apices. However, they can also point upwards or outwards.
Lastly, while crassinervium occurs closer to the coastland and much lower altitude, alternans occur at a higher one and a little far from the coastline.
How to care for your Philodendron crassinervium plant
Philodendron crassinervium thrives best in a warm, humid area with bright indirect light. Ensure the potting mix drains, is airy, and rich in organic matter and water when the top few inches feel dry.
Don’t forget it also needs repotting after 1-2 years, pruning, and feeding once a month with a balanced liquid fertilizer for a houseplant.
Here is the care P. crassinervium care and growing needs summary:
| USDA hardiness zone | 10-11. Not frost resistant. |
| Temperature | 60-80°F. Avoid cold drafts and sudden temperature changes, and don’t place your plant near heat, cold vents, or appliances. If grown outdoors, move your plant inside your house when the temperature falls below 50°F, |
| Humidity | Ideal humidity is 60% or more, but these plants can tolerate up to 40%. Mist your plants, buy a humidifier, have a pebble tray, or group your plants to help raise humidity if yours is too low. |
| Light | Bright, indirect light. Avoid direct hot sun and use grow lights if your house doesn’t have enough light. |
| Potting mix | Grow your Philodendron crassinervium in a well-drained, aerated potting mix rich in organic matter. We recommend you buy or make an aroid mix. |
| Watering | Thoroughly water when the potting mix feels dry up to the first knuckle, or your soil moisture meter reads dry. Don’t forget to discard any water that collects in the saucer. |
| Feeding | Since it grows slowly, you need not feed it much. I recommend feeding once a month with a good liquid houseplant fertilizer and half-recommended strength only during the growing seasons. A slow-release formula or any good houseplant fertilizer should work well. |
| Pruning | Remove dead, damaged, or diseased leaves whenever you spot them. Use sterilized gardening shears. Also, you can cut it back a bit if it grows too large. |
| Repotting | After 1-2 years or when root bound. Use a pot 2-3 inches wider in diameter. |
| Moss pole | Only necessary if you want it to climb, and you should train. Otherwise, it can grow just fine while creeping. |
Issues or problems
You are unlikely to have any serious issues if you grow this plant in ideal conditions and with proper care. However, like any other Philo, it may have pests, diseases, or root rot.
Also, leaf curling and discoloration (turning yellow, brown, black, or having brown tips and edges) can occur with the wrong growing conditions and care.
Frequently asked questions
Is Philodendron crassinervium rare?
Yes. While considered relatively abundant in its natural habitat, P. crassinervium is a rare and hard-to-find houseplant. I have not seen it at big box stores or large-scale horticulturalists.
What is the price of Philodendron crassinervium?
Philodendron crassinervium price ranges from $30 to $60. How much you pay will depend on where you buy it and the size. Larger, more established plants will cost more.
Where do you buy Philodendron crassinervium?
If you are looking for crassinervium, Etsy.com, Instagram, Facebook, and eBay are the best places to find it. These online shops and social media platforms have vendors from the US and the UK, Canada, Australia, Asia, etc. Also, a couple of websites sell this plant in the USA.