Philodendron “Rojo Congo” Care Guide

Even though the Philodendron “Rojo Congo” (a hybrid of the Imperial Red and P. tatei subsp. Melanochlorum) boasts remarkable visual appeal, it is surprisingly easy to cultivate.

The Rojo Congo is more prominent and broader than other red varieties, has deeper red leaves, and develops far more quickly. This tropical Philodendron may grow up to four feet tall and just as wide indoors. The Philodendron “Rojo Congo” is often listed among plants that can withstand neglect.

The Rojo Congo’s new foliage will start as light green with red undertones, turning brown to coppery red before maturing into a deep dark green color with a hint of red. It is an exquisite plant and a delight to grow if you stick to the basics.

Philodendron “Rojo Congo” Care Basics

Below is a table with the essential environment variables that, if followed, will allow your Philodendron “Rojo Congo” to flourish. We’ll explore each of these in more detail below.

Light:Dappled or partial shade.
Water:Water only when the top third of the pot’s soil is dry. Tolerates drought better than continuously wet soil.
Soil:An organically rich, well-draining soil
Humidity:Between 40-60%
Temperature:Rojo Congo is happiest at 68 – 86 ⁰F (20 – 30 ⁰C)
Fertilizer:A regular application of diluted fertilizer
Pruning:Prune only if plant proportions get too big or for propagation needs
Repotting:Repot when root density compromises watering efficiencies.

Is the Philodendron “Rojo Congo” a Hybrid?

Yes. Philodendron Rojo Congo is a hybrid of two hybrid parents. While some well-meaning care guides will tell you the plant is native to Africa or South America, it’s native to a laboratory, as both parents are hybrids.

Philodendron “Rojo Congo” Parentage

Philodendron “Rojo Congo” is a hybrid of the Imperial Red and the Congo.

Philodendron “Imperial Red”

Imperial Red, or the blushing Philodendron, is a hybrid of unknown parentage but is patented under the Patent/Plant Breeders’ Rights: PP6,337 (1988). A direct quote from the patent follows:

The new cultivar was discovered growing among several hundred random seedlings obtained in approximately September 1977 from Bamboo Nursery, Opapka, Florida.

The plants were approximately 3-4″ long with roots but not rooted in the soil and were indistinguishable one from the other at the time of purchase.

The parentage of the new cultivar was not known at the time of acquisition, nor is it now known.

A philodendron plant named Imperial Red is mainly characterized by its rosette plant form, relatively large leaves which are generally brown-maroon when immature to dark green-maroon when mature; fast and compact growth habit, and compact form; close and symmetrical internodes, dark green petioles with red-purple sheaths, and by its efficient propagation by tissue culture.

Philodendron tatei subsp. Melanochlorum “Congo”

P. tatei subsp. Melanochlorum “Congo” is a hybrid of the P. tatei subsp. Melanochlorum is patented under the Patent/Plant Breeders’ Rights: PP11,724 (2000). A direct quote from the patent follows:

Its self-heading, not vining, mainly characterizes a new and distinct cultivar of Philodendron named Congo self-supporting appearance; large plant size; mostly upright, somewhat outwardly spreading and open plant habit; good vigor and rapid growth rate; early and freely branching; large, thick, leathery and glossy dark green leaves; and relatively long petioles with long, slightly grayed, orange-colored petiole sheaths.

The new Philodendron is a product of a planned breeding program conducted by the Inventor in Altha, Fla.

The objective of the breeding program was to develop new Philodendrons that were self-heading, not vining, and self-supporting with distinctive plant form and growth habit, thick leaves, rapid growth rate, and shorter petioles than plants of the parent selection.

The parent species is thus described on CATE Araceae:

The P. tatei is a climbing herb up to 10 ft. (3 m) long and is leafy throughout. It has a thick stem with s abbreviated internodes, hidden by ferruginous cataphylls (an iron-colored rudimentary scalelike leaf that precedes the foliage leaves of a plant).

New cataphylls are 8 inches (21 cm) long, drying, persistent, and slowly breaking up.

The P. tatei leaves are sheathed for 2 inches (5 cm) in the lower part. The leaf blades are up to 16 inches (40 cm) long and 7 inches (18 cm) wide and glossy on both surfaces, with greenish-pink margins.

‘Congo’ is a free-branching, non-vining philodendron that is non-vining. The large, glossy, dark green leaves sit upright.

They are happily grown in bright, shaded positions indoors or in protected outdoor places. Indoors it grows to 5 feet (1.5 m) and has a width of 28 inches (70 cm).

Relation to Philodendron Birkin

The variegated Philodendron Birkin is a radiation-induced chimeric mutation of the Philodendron “Rojo Congo.” Read my Philodendron Birkin – The Ultimate Care Guide for advice on that plant.

Caring for Philodendron “Rojo Congo”

Now that we have looked at the parent’s needs, we know what our Rojo Congo Philodendron needs. Let’s break it down.

Philodendron Rojo Congo Size & Growth

Most philodendrons exhibit a fast growth pattern, and the philodendron Rojo is no exception. With a size that can reach 5 x 5 feet (1.5 x 1.5 m), you will need to control its growth by cutting it back whenever necessary.

Because it can spread to as much as its height, it also needs quite a bit of space around it. This is not a small apartment plant; it requires a lot of space and looks best in larger homes or offices.

Philodendron Rojo Congo Light Needs

Philodendrons can flourish in environments with relatively low light intensities, as evidenced by the fact that many of them may be found in nature beneath the canopies of densely foliated trees. This factor makes Philodendron “Rojo Congo” so suitable as houseplants.

According to the University of Illinois, Philodendrons are low-light plants, meaning you can keep them at the North-facing window (in the Northern Hemisphere).

In the Northern Hemisphere, medium bright light (250 – 1000 foot-candle) indoors will be provided by the sun entering an east or west-facing window. The sun entering south-facing or west-facing windows will provide high indoor light (500 – 1000 FC).

Most plants require some daily darkness to develop correctly. A maximum of 16 hours of light will boost growth without interfering with the plant’s circadian clock.

This is especially critical if artificial light is a factor in the area where the plant is kept.

Plants generally need light above 750 foot-candles for optimum development. You can provide that by giving them artificial light that is 15 watts or more per square foot of growing space.

For plants that require low to medium light levels, a fixture with two fluorescent tubes is enough.

Philodendron Rojo Congo Water Needs

Overwatering is the main reason why potted plants die. When surrounded by water, roots can’t breathe – as crucial to roots as to humans.

The general rule is to only water when necessary. To decide when to water, one may utilize the following techniques:

  • Tap the Pot: When potting mix in a clay pot starts to dry up, it shrinks away from the pot’s sides. Use a stick or your knuckles to tap the pot’s side. If the sound is hollow, add water; if the sound is dull, the soil is damp and thus still pressing against the pot.
  • Touch-Test: The most accurate test for soil moisture is to feel how dry the potting soil feels. If the mixture is dry at your fingertip after inserting your finger up to the second digit, it needs water.
  • Estimate weight: It’s easy to see a weight reduction as potting mixtures dry up.
  • Assess soil color: As potting combinations dry, their color will shift from dark to lighter.

Deep watering removes accumulated salts and ensures that most of the roots in the bottom two-thirds of the pot get enough water. Empty the tray, and don’t let the pot sit in the accumulated water.

You must use a pot with plenty of drainage holes on the bottom corners for the best results. The tray often blocks drainage holes only on the bottom – unless you space them off the tray.

The Role of Water in Plant Care

Water serves many critical functions in all living organisms. In plants, water plays a pivotal role in photosynthesis. It is a transport vehicle for mineral salts (ions) and carbohydrates. Water also performs other functions in your plant’s life:

  • Water as a Constituent – 80–90% of the fresh weight of herbaceous plants is made up of water.
  • Water as a Solvent – most compounds readily dissolve in water and serve as a medium where biological reactants dissolve in cells for chemical reactions.
  • Water as a Reactant – for biochemical reactions such as photosynthesis. Water is also a reactant in the hydrolysis of plant food reserves like starch.
  • Water as Essential Transport – circulation carries the minerals from the soil across the root, up the stem, and throughout the plant.
  • Water as a Component of Growth – Small cavities (vacuoles) form during cell division, absorbing water that transports mineral deposits. As the water diffuses into the tiny vacuoles, it creates pressure inside the cell, causing them to expand and increase.
  • Water and Turgidity – water pressure against mature cells’ interior helps keep their form. Suppose the pressure is lost (for example, due to excessive evaporation, mortality, or exposure to salt solutions). In that case, the cells may lose their turgidity and become flaccid.
  • Water and the Plant’s Thermal Stability – plants may absorb a large quantity of heat (such as from sunshine) without radical temperature increases. The high water content in a plant helps stabilize temperature fluctuations.

Philodendron Rojo Congo Soil Preferences

Philodendrons grow well in a porous blend of an inert and organic potting medium that retains moisture but drains effectively. Philodendron “Rojo Congo” needs soil that drains well yet can retain moisture.

Our ideal soil will provide our plant with adequate aeration (avoiding anaerobic conditions), maintain the proper pH, and ensure the soil has sufficient cation exchange capacity (CEC).

Suppose you’ve had the opportunity to read my Composting Masterclass book. You’d understand why I’m so passionate about compost, even in potting soil. A good potting mix for your Splendid Philodendron should include the following ingredients in the given proportions:

  • One part compost (25%)
  • Two parts coconut coir (50%)
  • Half a part of pumice (or perlite) (12.5%)
  • Half an amount expanded shale, or LECA (lightweight expanded clay aggregate) (12.5%)

Philodendron Rojo Congo Fertilizing Needs

Ordinary “house plant” fertilizer used according to label directions will suffice when fertilizer is needed. Philodendron Rojo grows fast and needs fertility support,  so regular feeding using a diluted mix is better than strong fertilizer occasionally applied.

Suppose your plant is doing poorly, i.e., not developing as fast as before, shooting smaller leaves than before. In that case, you should use fertilizer to boost its development.

As with water, too much fertilizer can harm the plant more than it helps. Overfertilizing can also become an issue, so follow dosage recommendations. Start with a weaker solution and test it to see how your plant does.

Potting & Repotting Philodendron Rojo Congo

Select a pot that can support the plant’s top since this is a heavy plant once it grows. Terracotta or ceramic pots are not only beautiful, but they’re also helpful in preventing this top-heavy plant from toppling over.

On the other hand, plastic is lighter and holds moisture for a more extended period. Plastic pots are great when the plant is little, but when it starts to topple over, switching to a more sturdy pot is preferable.

The plant outgrows its present container as it grows, so you’ll need to transplant it into a larger container. Repotting should be done in early spring to coincide with the start of a growing season, allowing the plant time to reestablish itself.

Whatever pot you choose, drill several holes in the bottom to drain any extra water.

How to Propagate Philodendron Rojo?

Propagation of philodendron Rojo can be achieved either by dividing (removing a part of the root with a stem) or rooting stem cuttings in water or soil.

Regardless of the method, keep the new plant or cut out of direct sunlight in a warm, bright location. Keep the soil moist, making sure not to overwater. In 6-8 weeks, you should see new roots or growth form.

Is Philodendron “Rojo Congo” Toxic?

All philodendrons are poisonous due to their varying amounts of raphides or needle-shaped calcium oxalate crystals. These crystals act as a defense mechanism in nature against herbivores. Crystals of calcium oxalate irritate delicate interior tissue as well as the skin.

Accidental intake causes severe throat and mouth burning, requiring rapid medical intervention. Philodendrons should therefore be kept out of the reach of youngsters and animals.

In Closing

The Rojo Philodendron variety is a fast and large-growing variety. It’s self-heading, making it a great floor plant.

Like other varieties, it doesn’t require much care and attention. Still, protecting it from direct sun and low temperatures is essential, and even high temperatures (100 ⁰F (38 ⁰C)) are problematic.

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