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The Exotic Rainforest
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Within our collection we have over 80 plus species of
Philodendron
If you are seeking other photos, click this link

New: Understanding, pronouncing and using Botanical terminology, a Glossary
"Much of what we believe is based on what we have yet to be taught. Listen to Mother Nature. Her advice is best."
 

Growing Tropical Philodendron Species
 How to cultivate, grow, identify and cause a Philodendron to reproduce.
Researched and written by Steve Lucas
 

 
Dr. Thomas B. Croat, Missouri Botanical garden research greenhouse, Photo Copyright Janice Lucas, www.ExoticRainforest.comThe botanical information on this page is based on the scientific journals of aroid botanist Dr. Thomas B. Croat Ph.D., P.A. Schulze Curator of Botany of the Missouri Botanical Garden in St. Louis, MO.  Dr. Croat was honored in the summer of 2008 for having collected over 100,000 specimens in the wild.  My thanks to aroid expert Julius Boos, aroid, palm and cycad expert Leland Miyano, aroid pollination expert Dr. Marc Gibernau and expert aroid grower Russ Hammer for their input. 

My sincere thanks goes to my mentor Tom Croat for his continued personal guidance.


For a list of the majority of Philodendron species in the Exotic Rainforest collection with photos as well as keys to identify species, click here.

Note:
For help to identify a species shown below, click on any photo and you will be directed to
the page that gives the scientific name, common names if any, and description of that
Philodendron
species
.  Every photo on this page is linked to a page with an explanation. 
 
Note: Worried about the possibility of a Philodendron being poisonous? 
If you are concerned about calcium oxalate crystals read the information at this link!




Philodendron, where and how they grow in nature.

Philodendron verrucosum, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comPhilodendron species are divided into subgenera, sections and subsections in order to classify their individual characteristics.  The three major groups of Philodendron include Philodendron subgenus Philodendron, Philodendron subgenus Meconostigma (the "tree Philodendron) and Philodendron subgenus Pteromischum.   Species within the first two subgenera are commonly collected but species found in subgenus Pteromischum are rarely grown in private collections due to their specialized growing requirements.

With many species yet to be discovered there are an  estimated 1000 species (or more) of Philodendron that are common to much of Mexico, all of Central America, most of South America as well as a few Philodendron species on Caribbean islands.  Since Philodendron species are native only to these regions of the world, they are known as "Neotropical" species.  All are tropical and will not tolerate extended freezes. 

Philodendron species have been released into the tropical Pacific as well as Australia and Southeast Asia but are not found naturally in those parts of the world and have been introduced by man.  Philodendron "escapees" can easily be found among the flora of Hawaii and other exotic islands but are not native to those islands. 

Despite advice given on far too many websites indicating Philodendron enjoy infrequent watering that information is simply untrue!  Philodendron are rain forest species and during the rainy season often experience rain on a daily basis for up more than half the year.  People often just believe what they are told without doing any research on their own and those "old wife's tales" are almost always wrong!  If you listen to Mother Nature you'll find her advice indicates the correct approach to growing any plant species and Mother Nature gives her Philodendron plants lots of water.

In nature most Philodendron species live on the trunks or branches of trees and do not need soil to survive.  Those tree dwelling species are known as epiphytes or hemiepiphytes and are plants that live upon another plant.  Some Philodendron species may even grow attached to stone however only extremely knowledgeable growers ever manage to make a Philodendron grow successfully on stone. 

Relatively few Philodendron species grow in rain forest soil and are truly  terrestrial plants although a few species are consistently terrestrial.  There are species such as Philodendron renauxii from southeastern Brazil and Philodendron mamei from Colombia that are primarily terrestrial in nature.  Terrestrial species do not normally grow on a tree but Philodendron hastatum, the name was not changed to Philodendron domesticum as is claimedon the internet, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comsimply spread across the ground but terrestrial species are far outnumbered by the species that are epiphytic.  All Philodendron species vary in shape and size as they mature but within a species there is no such thing as a single leaf shape due to both natural variation and morphogenesis. 

 
An epiphyte (ep-a-PHYTE) is a plant that begins life as a seed placed on the branches or trunk of a tree by a rain forest animal in their droppings and grow attached to the host plant.  A hemiepiphyte is one that is an epiphyte for part of its life and can begin life growing as a seed dropped on the ground and then find a host tree to climb.  In nature, a seed is placed on a branch in the dropping of a bird or other rain forest animal who has eaten the fruit produced by the parent Philodendron's inflorescence.   A discussion of the inflorescence and fruit as well as seed production can be found later in this article.  Both epiphytic and hemiepiphytic plants drop long roots to dangle in the air in order to collect rain water.  Take a walk in any rain forest and you'll be amazed at the "vines" hanging from the branches that are often nothing more than roots!

Hemiepiphytes are divided into two groups, primary and secondary. Primary hemiepiphytes begin their life cycle as seeds that germinate on the trunk or limbs of a host tree in the same way as a true epiphyte. They then develop slowly until they are large enough to develop long aerial roots that eventually reach the ground.  Their growth strategy is to attain height in the forest as quickly as possible in order to reach a spot where the light is brighter. The second type known as Secondary hemiepiphytes begin their lives as seeds that germinate in the soil or on a tree trunk very near the ground. Their strategy is to quickly send their roots to the ground where they can gather additional nutrients from the soil. Secondary hemiepiphytes then climb the host where they morph into the adult form and sometimes completely lose their connection to the ground.  If an epiphyte manages to grow its roots all the way to the soil, by definition it becomes a hemiepiphyte.  Conversely, if a hemiepiphyte looses contact with the soil it becomes an epiphyte.

It appears their own DNA directs the secondary hemiepiphyte towards a tree so it can begin the climb toward the light and to adulthood. Dr. Croat explains,  "I suspect that it is auxin controlled. As you may imagine younger plants grow scototropically one assumes because they have to find a tree, rock or wall. Once there they stop growing horizontally and grow upward, effectively toward the light, rather than away from the light."  Scototropic refers to the behavior of a tropical seedling vine that grows toward dark objects. The plant does this as an adaptive characteristic that enables the young vine to grow towards the shade around the trunk of a large tree so it can eventually begin to climb in order to find brighter light.  Auxins are plant hormones that control the behavioral processes of the plant.

Philodendron renauxii Reitz, Paddle leaf Philodendron, Photo Copyright 2007, Steve Lucas, www.ExoticRainforest.comSome Philodendron start life 20 meters (60 feet) or more up their host and eventually drop roots all the way to the ground!  Before a Philodendron drops its long roots the plant may remain relatively small in blade size.  Once the roots hit the soil and the plant can gain extra nourishment it can become enormous in size!  Some epiphytic Philodendron species can grow leaves that are one to two meters (3 to 6 feet) in size and larger.  The tiny kitchen plant most know as "Philodendron scandens or Philodendron micans" (correctly known to science as Philodendron hederaceum) often grows 7 to 8 times the size in the forest it can be seen in a pot! 

 

 

The importance of trees in the rain forest

With the vast amount of rain forest destruction now underway in South America, few people realize the true importance of the loss of those trees that are now routinely cut down.  Even the U.S. government has encouraged South American governments to clear the rain forest in order to grow crops that can be used by other countries including the U.S. for the production of bio-fuels.  In many cases those crops were never intended to be grown in the poor soil tjat remains once the forest is gone so more and more trees and plant species vanish since those crops will only grow for a few years and the farmers must then cut down even more forest!.  Of all the plant species that live in the forest a full 66% are dependent on a tree for their survival. 

Not only do many plant species depend on the trees of the forest but so do many animal and insect species as well.  High in the canopy can be found many exquisite species of frogs, invertebrates and small mammals that never come down to the forest floor.  The live their entire lives on the branches of those large trees.

If you examine Dr. Scott Mori's chart below you will find that more species live in the trees than the total number of trees in the forest!  If we allow the rain forest to be devastated we are completely wiping out enormous numbers of plant and animal species by destroying their natural habitat.  If we allow the destruction of even a section of the forest we often destroy the habitat for many plant species as well as the insects and animals tha pollinate those plants and eventually that plant species vanishes from the face of the earth.  By simply looking at the "smaller pie slices" you will quickly see the importance of the forest trees to the survival of the majority of Philodendron species since they are epiphytic or hemiepiphytic.

The plant to the left above, Philodendron spiritus-sancti, is now extremely rare with only six known specimens left in the wild in Brazil as a result of rain forest destruction. 

The importance of trees in the rain forest, Chart Copyright Dr. Scott A. Mori, New York Botnaical Garden

 

"Tree Philodendron",  members of Philodendron subgenus Meconostigma

Philodendron bipinnatifidum Schott ex Endl, Philodendron selloumThe "Tree Philodendron" are found largely in Brazil, Argentina, Bolivia and Paraguay, Although quite a few websites claim species known as "tree Philodendron" that are members of subgenus Meconostigma do not climb that information has no basis in science. 

This claim is often made in regard to Philodendron bipinnatifidum (also sold as Philodendron selloum) which is often sold as Philodendron selloum.  In his scientific paper A Revision of Philodendron Subgenus
Meconostigma (Araceae) Dr. Simon Mayo of the Royal Botanic Garden Kew in London describes these species as being hemiepiphitic. 

Again, in the scientific text The Genera of Araceae by Mayo, Bogner and P.C. Boyce when
discussing the roots of climbing aroids the text states, "Roots in Araceae are always adventitious and dimorphic roots are often found in climbing hcmiepiphytes, e.g. Monstera deliciosa, Philodendron bipinnatifidum."  Adventitious roots form from shoot tissues, not from another root while dimorphic indicates the roots grow in two distinct forms. 

Philodendron bipinntifidum (Philodendron selloum) growing 100 feet in the canopy.Despite the belief Meconostigma species don't climb they do in fact climb to 30 meters or higher (100 plus feet).  When asked, Dr. Mayo responded to my query in a personal note.  "Yes Philodendron bipinnatifidum certainly does climb but from what I've seen the way it does it is different from Subgenus Philodendron and subgenus Pteromischum species which emit relatively fine anchor roots at or near the nodes. In P. bipinnatifidum and other members of Subgenus Meconostigma the anchor roots are pretty thick and can wrap themselves around small tree stems like ropes. It is almost as if the plant hauls itself into the canopy. I've seen plants suspended between neighboring small trees by these roots. They do have a very adaptable kind of growth habit, which I suppose goes along with their natural ecology, preferring rather higher light intensity situations than "normal"   "Tree Philodendron" do in fact climb.

 
Learn before and as you grow.

If you grow a Philodendron species such as plants known as Philodendron scandens, Philodendron oxycardium, Philodendron micans or one of the other names used for this single species it is wise to first learn just how the species grows in nature and then attempt to duplicate that condition (as best possible) if you wish to experience the species' natural beauty.   Due to variation and morphogenesis a single Philodendron sp. can assume many shapes.  Every one of the plants just named is the same exact species.  Just because they have differences in the leaf blades does not mean they are a different species.

There is no such thing as a single leaf form for any Philodendron species even though many people think all Philodendron sp. just look like dime store "ivy".   As can easily be see from the few photos on this page a Philodendron has no set shape!   Some are oval, some are round, some are spear shaped, some are shaped like the frond of a palm while many possess very strange shapes. 


Many plants known as "ivy" are not Philodendron species at all but instead belong
to Asian genera such as Epipremnum or Rhaphidophora. 

You can see a few of those species on this list. 

To understand natural variation and morphogenesis think of a Philodendron like your friends and family.   You know people who are skinny, over weight, tall people who are short and wide, friends with dark skin, light skin and many other human variations.  As a baby grows it changes (morphs) and no longer looks like a baby.  But all those people are still humans (Homo sapiens).  The same is true with Philodendron sp.  Within a single species you can have leaves that are tall, short, fat, skinny, dark, light, small, large and many other variables.  That condition is "variation".  This link offers a more complete explanation of natural variation within plant species in non-technical language:  Natural variation in species

Many Philodendron sp. can be reproduced through simply taking a cutting that contains at least one node (preferably two) on the stem for new roots to develop and grow.   Some growers believe you Philodendron pusillum, Photo Copyright 2010, Steve Lucas, www.ExoticRainforest.commust first place the node in water in to allow it to root, but  knowledgeable growers know you can simply place the petiole section with a good node or nodes in damp soil and it will root.  I've often taken stem cuttings with nodes and simply laid them on their side, partially submerged in soil, and a new plant will form.  In the rain forest there is no one around to cut the stem with a couple of node, place it in a jar of water and then pot it once it produces roots!  When a stem (commonly called the cane) falls to the ground in a storm nature finds a way to grow new specimens. 

 

Important parts of a Philodendron.

Parts of a Philodendron including the petiole, stem, root, leaf blade and cataphyll, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe shape of the leaf blade is important to a collector but is far less important to a botanist.  The blades of Philodendron species naturally in shape and a single plant is often observed to have many different shapes to its blades.  The blade may have no lobes or lobes that are clearly divided.  The upper portion of the lobe is called the back lobe or posterior lobe while the lower part is known as the front or anterior lobe.  The blade is divided down the center by the midrib which is a large vein.  The shape of the midrib is important to the identification of the species.  Running laterally from the midrib can be found the primary lateral leaf veins that may or may not be prominent, the interprimary leaf veins, and the tertiary or smallest venation.  All are important in the determination of the species.

The portion of a Philodendron that most people call the "stem" is actually the petiole. Despite common misconceptions the petiole is not a stem and is a term incorrectly used by collectors. The petiole is the stalk that connects the leaf blade lamina to the stem at the base of the plant.   The real stem is not the support for any single leaf but instead the stem is the base of the plant often called a "cane".    The petioles grow from nodes along the stem's length.  The stem sections that are the segments between two nodes are known as internodes.

When a new leaf begins to develop a cataphyll normally surrounds the newly emerging leaf.  The cataphyll is a bract-like modified leaf that surrounds any new leaf and whose purpose is to protect the leaf as it develops.  A cataphyll is any foliar organ that has no differentiation of petiole and blade and usually has either a single rib on the back side but often has no rib at all.  In the case when the cataphyll possess two ribs (double keeled) it is known as a prophyll.   Prophylls often form on species that have a growth structure known as being sympodial, a subject far tood complicated for this discussion.  The more common form of growth is known as being monopodial.  If you would like to know more about these two growth forms please click this link and read about our unique specimen collected near Limón, Ecuador.  The cataphyll is the single most important identifying characteristic any botanist uses to identify the species and is more important than the leaf shape due to their unique shapes.

At the base or axis of the plant the stem will be observed.  The stem may be rhizomatous and run across the ground or Rhizome stem, Philodendron pusillum, Photo copyright 2009 Steve Lucas, www.ExoticRainforest.comit may climb a host tree.  In some cases the stem will even grow attached to stone.  Along the stem can be seen the nodes from which the roots and petioles extend.  The sections that separate the nodes are known as internodes and their length and circumference can be used to help identify the species. 


This link will give you an explanation of the stem.

Another very important way of determining the species is to examine the inflorescence.  The inflorescence contains the sexual parts of the plant and is explained in detail later in this article.

 

Philodendron lacerum adult leaf blade, Photo Copyright 2008, Buddy PoulsenThis characteristic is not common but some (not all) Philodendron species are known as myrmecophytes that are plant species that live associated with a colony of ants.  Myrmecophytes possesses specialized organs that exude a sweet liquid or provide shelter or food for the ants. These Philodendron species often possess extrafloral nectarines or tissue from which the ants can draw nourishment.  The plant benefits by the protection from predators that try to eat the plant's leaves that is provided by these often fierce ants.  An extra-floral nectary can be born on the stems and the leaves as splotches with the color of a purple/reddish wine stain known as being vinaceous.   Although nectaries secrete sweet liquids to attract pollinators an extrafloral nectary does not produce its liquid for the purpose of pollination.  You will read more later in this article about insect pollinator attractants.  This characteristic should not alarm the home grower since the ant species attracted are not found in a home setting outside the tropics.

 

 

Species compared to hybridized Philodendron.


Although there are a very few natural Philodendron hybrids found in nature (such as Philodendron 'Marijke' (photo below, left), many Philodendron commonly sold at nurseries are hybridized plants and are not species.  The majority of hybrid names are simply made up and almost no information can ever be reliably found.  You'll just have to believe what Philodendron maximum K. Krausea grower tells you and that may often be incorrect since scientifically accurate information on hybrid plants is rarely available.

Hybrid Philodendron are created when the pollen from one species is applied to the spadix of another species at the time the plant is ready to reproduce.  The pollen of a hybrid may be applied to the spadix of another hybrid creating a further confused hybrid.  (An explanation of the spathe and spadix that are parts of the inflorescence of an aroid is found later in this article.)  The resulting seeds (if the hybrid even produces seeds since many are sterile) are not a species, but a hybridized  form.  Some hybridizers enjoy seeing just what they can create and after a period of time you have no idea what the parents may have been.  As a result, there is no way of knowing if the new hybrid prefers wet conditions, drier conditions, grows in the ground or high in the trees.  Although hybrids can be beautiful, my preference is to grow only Philodendron species that can be traced back to their natural habitat and better understood.
 

Philodendron Marijke (not a species), Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe majority of plants you buy in a nursery are juvenile forms and look nothing like the adult of the species.  Think about children that "morph" into adults.  A child looks little like the adult form but still has all the same body parts including the same number of arms, legs, fingers and toes that are not fully grown.  For many years botanists were confused by the differences in adult forms and juvenile forms and often tried to give each a different scientific name.  That is one reason some plants have numerous scientific names that can be worked back to the primary base name (basionym) using a source such as the International Plant Names Index (a service of the Royal Botanic Gardens, Kew in London) or TROPICOS (a service of the Missouri Botanical Garden).  One major goal of this website is an attempt to help collectors by doing some of that research for you and by consulting numerous botanical experts along with scientific databases.

 

Growing and watering Philodendron.

 
So how do you grow Philodendron species?  If you live in a tropical or semi-tropical climate you can simply put a Philodendron in the ground and allow it to climb a tree.  Otherwise, proper potting of a specimen is important if you want it to both survive and grow to reach its natural beauty. 

The common advice on most garden websites is to allow a plant to dry between watering that is often not good advice.  Anyone that has asthma knows the difficulty of getting air out and then drawing it back in.  Even though plants release Philodendron holtonianum, Photo Coprygith 2008, Steve Lucas, www.ExoticRainforest.comoxygen into the air through their leaves they draw fresh oxygen into the plant through their roots.  A potted plant is much like your lungs and if you can't bring in fresh oxygen you will soon cease to live.  As a result the top layer of a potted plant's soil should not be allowed to dry since that dry soil prevents the intake of fresh air!  Once the soil dries it creates a "blanket effect" to hold in the stale moisture and keep out fresh oxygen.  Once the soil dries the moist layer below cannot easily breathe in order to re-oxygenate the soil that soon becomes anoxic. Anoxia causes root rot,  The dry upper layer actually prevents the capillary effect of the wet surface evaporation when damp soil is exposed to air.   When you pour water in the air inside the soil is displaced so the oxygenated air inside has left the pot. If the upper soil layer completely dries the "lungs" of the pot cannot work and can no longer continue to draw in another breath of fresh air. 

The entirety of the soil needs to remain evenly damp so the roots of the plant can continue to draw in fresh oxygen.  Otherwise, root rot is likely to begin.  Since most people don't want to bother with ever watering their plants, many people go into a garden store and a very rich potting soil that stays soggy all the time.  Despite the belief that are giving the plant "rich" soil to make it thrive they may be dooming their Philodendron specimen to death.  Philodendron species can literally drown in mucky soil due to a lack of oxygen! 

For some unexplained reason many growers believe the rich soil makes a Philodendron grow better!  Typical "potting soils" just don't work for the vast majority of Philodendron species since , most grow in trees, not in soggy soil.  A Philodendron species' roots are designed to collect rain water during the wet season and suffer through the dry season.  But even in the dry season a Philodendron sp. can collect enough water from the humidity around their exposed roots to survive.   

Although house plant growers commonly believe tropical plants do not need water in winter that belief is simply a myth. Tropical plants live in very humid conditions and are capable of gathering water directly from the air even during the drier portions of the year when it doesn't rain on a daily basis.  Dew and fog are very important contributors to the water available to a tropical rain forest plant species and homes don't have dew or fog!  If we deny the plant the water they crave they only suffer and will never be able to display their natural beauty.  In the temperate rain forest the amount of water available  from the dew alone is estimated to be between three to five percent of the total annual precipitation!   As a result, your tropical Philodendron species need water year round but it is wise to reduce the amount offered during the winter.

The photo to the right is of our personal collection of rain forest plant species that includes almost 100 Philodendron specimens.  We water every week of the year averaging four days a week in summer and three days per week in winter.  As can be seen in the photo the plants love water.

Despite the belief of far too many growers, growing plants is not just about the water content of the soil!  The advice to water only once a week and keep the top two inches of the soil dry is not always good advice!  Many aroids and other plant species grow in very wet soil! 

Instead it is about the fast flow of water through the soil or the lack thereof that causes a lack of oxygen, anerobic fermentation and saprophytes that turn into pathogens.  Saprophytes are organisms including fungus or bacteria that grow on and draw nourishment from dead or decaying organic matter that often includes soggy wet soil. The pathogens attack the roots and cause them to rot so all of the advice to "slow down on the water" is really about how to control the pathogens.

Fermentation and saprophytes often occur in muddy soil that will not not allow the roots to breathe but they don't necessarily occur in water which is why we can cause a plant that is about to die to grow new roots in clean water.  As a result, it is necessary to use soil mixes that allow the roots to breathe and will not remain soggy. I've attempted in many threads to explain the necessity of mixing proper soil for plants but the advice is often ignored since it requires some "work" on the part of the plant's keeper. The reason plants rot is not the amount of water given to the plant! These are rain forest plants and are literally drowned for months at a time!

If you could visit a rain forest you would quickly learn the soil is composed of leaf litter, decaying wood, compost, animal droppings and the charcoal left behind when a part of the forest burns. If we'll just listen to Mother Nature we can all make our plants grow as they do in nature. That is precisely what I attempt to explain when I recommend mixing soil, not just buying a bag at the store. Over time we've arrived at a soil mixture for most of our aroid species which duplicates the rain forest. We use this mixture on the advice of the aroid keepers at the Missouri Botanical Garden in St. Louis. The goal of this mix is to allow the roots to freely find places to extend and grow without constantly finding wet places where they will rot. This mix will remain damp but drain quickly and as you can see from the photo above will make the plants thrive.

Rather than using a rich, soggy soil and watering only once a week (or less), use a soil that holds moisture well but drains quickly.  With the help of botanical garden researchers we've developed a soil mixture for most of our Philodendron sp. that works great.  People who visit our artificial rain forest are often amazed at the size of many of our specimens that grow much faster and larger than they often do in a home.  

The exact mixture is not critical but we use a soil mixture composed of approximately 30% soil, 20% peat, 40% orchid bark with charcoal , 10% Perlite and some finely cut and shredded sphagnum moss works well.  We also make our own compost and add it in place of some of the peat and bark  when available. We often add extra hardwood or aquarium charcoal to help purify the soil and sometimes volcanic rock.   We often add extra hardwood charcoal to help purify the soil and sometimes volcanic rock  The  charcoal is used to increase drainage but also to take advantage of the tiny air spaces in the charcoal for growing beneficial microbes.  It helps with water retention, as well.  If you have some good compost feel free to add it.  Small pieces of charcoal can be purchased from any good orchid supply.  If you are concerned about your soil remaining wet just add more orchid mix, cypress mulch, Perlite and sphagnum moss. 

We grow many different Philodendron species in this basic mixture and some of our specimens have reached their adult or near adult size and regularly produce a spathe and spadix (inflorescence).   The goal of our mixture is to cause the water to flow through the soil quickly, remain slightly damp, but never soggy.  The roots of our plants attach to the bark just as they do in nature on the side of a tree.  Most growers call a mix similar to the one we use a "jungle mix".

 
I've had several "nursery experts" write to tell me my soil mixture won't work due to the orchid potting media and mulch.  They claim the bark and mulch will eventually rot and create air pockets in the soil and then kill the plant.   My suggestion is they first visit any tropical rain forest and examine the soil then talk to the experts at Missouri Botanical Garden since they use a very similar mix for thousands of extremely rare wild collected type specimens in their herbarium collection that contains some of the only known specimens of Philodendron species in the United States!
 
Although you may be able to water less often in a home, in our artificial rain forest we water four or more days a week (sometimes daily during the heat of the year) and two or three days a week in winter.  There are species that prefer a longer dry period and we attempt to segregate those during the winter season.  Remember, Philodendron species normally grow in a rain forest, not a living room or kitchen!   Philodendron sp. prefer to to have their roots damp all the time, just not soggy.  Since In your home your plants are not likely to experience the natural heat and humidity of the forest, water often enough to keep the soil damp and be certain the pot can easily drain.  

 

Fertilizing Philodendron.

 
Philodendron warszewiczii sub adult leaf blade Copyright Steve LucasWhat about fertilizer?  In nature a Philodendron receives only natural forms!  The epiphytic species can collect minerals in the rain that comes from the winds blowing across the Atlantic from Africa but more often they collect decomposing debris that collects around their roots.  Philodendron often collect  dust from major dust storms in the African plains carried by the high altitude winds to the rain forests of tropical America.  Once that dust settles in the rain the long dangling roots of the plants does gather a small amount of dissolved minerals and nutrients.  But nothing like home growers are prone to offer! 
 
More frequently a Philodendron specimen collects falling dead vegetation that decays around their roots and provides nourishment.  Even the species up in the canopy collect falling debris in the form of dead leaves and convert that debris to a natural fertilizer.  Aroid expert Julius Boos wrote, "It is also the epiphytic plants that benefit just as much from falling debris and rain! Many 'birds-nest" type plants actually grow on trunks and branches of trees.  In French Guyana we saw a species of Philodendron that grows like a vine up tree trunks, and when it reaches a suitable spot, changes form from a climbing vine and becomes a 'birds-nest', catching leaves.  It then creates an area where ants actually build their nest in the roots and amongst the leaves/debris mix. These ants also provide lots of fertilizer with their by-products, left-over insect and fruit parts, etc.. The rain also washes debris and the Philodendron cordatum Kunth, Philodendron Angra dos Reis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comnitrogen it picks up and contains on to the long, pendent roots of other species."   Species, such as the terrestrial forms are designed to collect falling vegetation.  In nature, those species can often be found with piles of dead leaves and plant material at and inside their conical base.  That material decays and the result is a natural fertilizer, especially when insects are invited to set up home. 
 
Often collector/growers carefully clean out all dead and decaying material found around their plant!  By keeping the plant pristine you are depriving the plant of a natural form of fertilizer for the sake of "beauty".  We recommend using a dilute fertilizer at 10% to 20% of the manufacturers suggested level given frequently.  A good rule of thumb is to fertilize "weakly, weekly".  An alternate method used by successful commercial aroid growers is to use the pellet form of Osmocote 14-14-14 or Nutricote 13-13-13.  Osmocote is available at most home improvement stores while Nutricote is sold through agricultural suppliers.  The pellet fertilizer lasts 3 or more months and dissolves slowly.

 
Correct temperatures and humidity for Philodendron.

Temperature?  All Philodendron species are tropical.  That means they just can't tolerate cold temperatures for extended periods and in most cases a freeze will kill the plant.  Some do not appreciate the temperature of an air-conditioned home for long periods of time!  As a general rule, don't allow the temperature around your Philodendron specimens to drop below 12.75C (55 degrees F) if at all possible.   It is best to keep them below 90 degrees F which is not particularly difficult if you grow them in some form of shade or filtered light.  Some species will tolerate short periods of cold, such as Central Florida.  But most won't survive anywhere outdoors north of Zone 9.  Zone 10 is best!  Many will simply die if exposed to a freeze.  Since most demonstrate much faster growth when the temperature is in the 80 to 88 degree range you may find your specimen will appreciate being allowed to live outdoors during the spring, summer and portions of the fall.

Humidity is extremely important!  Do everything possible to keep the humidity high around your Philodendron most of the time.  These species live in a jungle that can have a humidity level near 100%!   If you live in a climate that has a low humidity you'll need to provide a method of giving the aroid more humidity.  In our rain forest the humidity is always high (85% or higher) due to the pond in the center of the room and frequent overhead misting!  Some growers keep their Philodendron near a swimming pool to allow for a constantly high humidity.   Air circulation is equally important since the air is almost always moving in the rain forest.

 
If you can't give the species rain forest humidity there is an alternative, an attractive shallow dish that can sit beneath the plant's pot.  Fill that pan with gravel, preferably one that does not have too much limestone.  Fill the pan and gravel with water and then sit your plant and pot on top of this gravel bath in to create a micro-climate around the Philodendron.  It works since water will evaporate around the leaves and fool the plant into believing it is living in a humid environment.  When you water the excess will simply drain into the gravel pot.   

 

Proper light for Philodendron species.

 
The next thing to consider is light.  In almost any rain forest, light is a very precious commodity!  Plants fight for position and large ones often deprive small specimens of almost any light!  That is the reason Philodendron sp., and other species, are climbing a tree, they are trying to reach the light!  As they grow high on the side of the tree field botanists see them morph into what appears to be a different species!  This new morphed "form" is just the adult leaf shape of the juvenile plant. 
 
In 2007 I watched a specimen of Philodendron bipennifolium sell on eBay for well over $70!  P. bipennifolium is a fairly common plant often called a Fiddle Leaf or Panda Philodendron you can normally for just a few dollars.  So what was unique about this one?  It was the near adult form that is rarely seen in collections!   As a result, the seller  was offering Philodendron bipennifolium as an "unknown" species from French Guiana!  The shape of the adult is so different once the plant reaches the fully adult form people were bidding very high amounts in an attempt to possess a "rare" specimen!  But with proper care and conditions you can grow one to that size and shape yourself.  It just takes time and something tall to climb!  It took 5 years but the plant to the left is now morphing into an adult.  As you can observe, there are still very juvenile leaf blades on the plant but other leaves have finally begun to morph.
 
The trick to seeing them morph is to allow the Philodendron to climb something like a tall piece of wood or a tall totem which can be purchased at many plant supply businesses.  The higher the better!  Many Philodendron won't morph into adults until they reach three to six meters (ten to twenty feet), sometimes more.  Some growers use what is known as a "wet" wall.  The wall is actually covered with wire and filled with sphagnum moss while a small pump spreads water across the top of the wall's face.  Philodendron love to climb this type of wall and often reach their adult size more rapidly.  Once you've provided the specimen something to climb such as a totem, wood or a wet wall and given it the light level it is trying to seek you'll be amazed at how it grows and changes shape.  Just avoid direct sunlight in most cases
 
Far too many growers put Philodendron in their bathrooms in very low light because the specimen is capable of surviving in that light level.  But that is not what it truly wants or needs!  I often read where people give "advice" on garden websites that Philodendron sp. should always be grown in very low light.  Wrong!  Just goes to show you how much bad information you can find on the internet about tropical plant species.  Philodendron rarely like full sun light, although a few will survive, but they do want relatively strong indirect light similar to that found right on the edge of a forest. 


 
Why does a Philodendron appear to cry?


Have you ever noticed your Philodendron "weeping"?  It is not uncommon to see water dripping from the leaf tips.  Although many growers assume the liquid is a result of dew it would be unlikely to observe dew forming inside a home on a house plant.   Even the droplets of water seen on grass in morning are frequently caused by guttation, rather than dew.

Guttation of Philodendron hederaceum, Photo Copyright 2009, Steve Lucas, www.ExoticRainforest.comAroids and other plant species possess glands known as hydathodes that are capable of producing a clear liquid through a process known as guttation. The word guttation is derived from the Latin word gutta "gut-TA" meaning droplet.  Excess moisture in the leaf blade normally transpires through pores of the leaf blade and is evaporated by heat and wind.  During periods of low temperatures and still air motion the water just accumulates at the leaf's tip.  Although sometimes called "sap" on plant discussion websites guttation is just the watery liquid that comes out of the plant and is common especially at night.

During the heat of the year the warmth of the sun pulls the water inside the stem (base of the plant)
through the petiole (support of the leaf blade) to the lamina of the leaf so the blade is filled with water.  Natural evaporation causes the water to be raised upwards.  When evaporation is not "pulling" the water out of the plant as a result of the lower natural temperatures during fall and winter the water inside the blade has no place to go and must find a method of escape since the petiole and stem are already filled. The water just seeks the easiest route out of the plant and chooses a gland. The weight of the water builds pressure pushing downward on the petiole toward the stem and finally builds to a point where the plant is simply forced to release the liquid through the leaf.  

Guttation commonly happens at night when the transpiration rates are naturally low.  It is possible for guttation to occur when the hydrostatic pressure is insufficient to prevent the flow of water into the xylem. The xylem is a plant tissue of various cells that is capable of transporting water and other substances including salts to the leaves.  Guttation frequently occurs in tropical plants when high humidity inhibits the natural transpiration or the loss of water vapor inside the plant to the outside air.

Guttation often occurs through the hydathodes that are found on the leaf tips of many Araceae (aroids). A hydathode is a modified stoma which is normally involved in photosynthesis that must secrete water as a result of the pressure of the excess water. The hydathodes of Araceae are commonly localized in the leaf tip but may be found elsewhere on the leaves.
 

 

Philodendron reproduction.

 
All Philodendron sp. are aroids.  An aroid is a plant that reproduces by producing an inflorescence known to science as a spathe and spadix.  Many people think the spathe is a "flower" but it's more like a flower holder.  The spathe is nothing more than a specially modified leaf or bract.   In botany a bract is a modified or specialized leaf that is associated with a reproductive structure of the plant. Flowers contain near microscopic sexual parts including anthers, stamens, and stigmas when the plant is in the reproductive process. 

A spathe contains none of these sexual characteristics but all can be observed on the true flowers along the spadix.  If you explore the inflorescence, there are very tiny flowers but they are found on the spadix at the center of the inflorescence.  The inflorescence is sometimes shaped like a tube or hood is made of several parts.  The portion that appears to be the "flower" is known as the spathe and inside that is the spadix that somewhat resembles an elongated pine cone.  The spadix is a spike on a thickened fleshy axis that can produce tiny flowers.  When ready to reproduce, the spadix of a Philodendron produces both male, female and sterile flowers.  These are normally separated by the sterile zone.  The tiny male flowers produce pollen and the tiny female flowers are designed to be receptive to pollen.  However, most are cleverly divided by nature to keep the plant from being self pollinated.  The male flowers don't always produce pollen at the same time the female flowers are receptive.  Nature's preferred method is to have insects pick up the pollen from one plant and carry it to another plant to keep the species strong. 

 

If you find the reproduction of a Philodendron of interest please visit this page on
natural and artificial aroid reproduction

 

Philodendron are not difficult to grow.

 
Growing Philodendron species is not difficult.  Only a few are hard to grow, and most will grow fairly well under a wide variety of conditions.  Remember, they often begin on the rain forest floor in relatively low light and spend years climbing Philodendron camposportoanum- juvenile,  Copyright Steve Lucasup to the light level they have been seeking.  The key is allowing them to climb, fast draining soil that stays damp (rarely dry), and good light that is relatively bright.  It's just that easy!

Although much has been covered in this short article there is far more to learn!  I strongly recommend each of you consider joining the International Aroid Society in order to learn even more.  Through the IAS discussion forum Aroid l you can ask questions to many of the world's top Anthurium experts and be assured of a qualified answer.  You'll also receive an annual copy of the IAS journal Aroideana which is highly respected in the scientific community as well as four quarterly  newsletters.  Annual membership is only $25.00 per year!
        

 

 Steve Lucas
                   Curator, The Exotic Rainforest
                
  Steve@ExoticRainforest.com

S



Click the link below for information:

 

For even more information, join the International Aroid Society:  http://www.exoticrainforest.com/Join%20IAS.html

 

 

 

Need more information?  Looking for information on a specific species?  Check our collection list of specimens for more information about the species we grow: http://www.exoticrainforest.com/plantscollection.html   

Incredible aroid botanical photographs by botanist David Scherberich
http://www.aroidpictures.fr/pictures.html