University of Vermont Extension
Department of Plant and Soil Science
Anytime News
Article
PHILODENDRONS
Dr. Leonard Perry, Extension
Professor
University of Vermont
Philodendrons have been popular
houseplants since Victorian times as they are easy to grow and
propagate, and
in more recent times attractive new selections are being sold.
These
new cultivars (cultivated varieties)
have interesting leaf shapes and many are colorful. Research has shown
philodendrons to be among the best houseplants for removing toxins from
air.
There are over 200 species of
philodendrons native to the American tropics, although only a few of
these,
along with some hybrids, are readily found as houseplants. Being
tropical they prefer bright, indirect
light but can tolerate lower light in many homes. Too much light
may
cause brown patches on
leaves. Remove these leaves and place in
less direct light. If plants are spindly
or not growing, give more light if possible. A plant light on a timer
may help.
Being tropical they prefer moist
air too, but can tolerate and adapt somewhat to the lower humidity,
especially during
winter, found in most homes. It helps to
mist plants daily once or twice. If this
isn't feasible, keep near a humidifier or place on a tray of pebbles
you can
keep moist. Too dry air, or plants kept
too dry, may cause leaves to turn brown and shrivel.
Being tropical is an indication
they prefer warm temperatures, generally between 60 and 75 degrees
F.
If areas on leaves turn black, this may
indicate they got too cold.
For a growing medium, a
houseplant mix works well. They can be
repotted any time. If they get too large
or need pruning, stem pieces root readily simply placed in a jar of
water.
Keep plants watered, but don't
overwater. Too dry and leaf tips may
turn brown. Too wet
and leaves turn yellow and plants may wilt even though the soil is
wet.
Fertilize lightly, according to
label directions. For many liquid
fertilizers this may be once in spring or summer, or during active
growth, and
less to none if not growing in fall and winter.
Pale leaves overall indicates plants may need a bit more fertilizer.
As with other houseplants with
broad leaves, dust periodically or give a rinse in the sink or
shower.
They usually don't get pests, but inspect
weekly for mealybugs, scales, and mites.
You should keep philodendrons away
from children and pets if they may chew the foliage. Being in the
large arum family, along with
plants such as dumbcane or Chinese evergreen, they contain calcium
oxalate
crystals which may cause a rash on the skin and will cause a painful
burning
and swelling of mouth and throat if ingested. Placing plants out of
reach, or
growing as a hanging basket, may be all that is needed.
Philodendrons often are found in
hanging baskets, as some of the more common ones are trailing or vining
but
don't climb. Often they may be sold
attached to a wooden slab as a "totem". The fiddle-leaf
philodendron
(P.
bipennifolium) with fiddle-shaped leaves to a foot long is one
common
example. There are selections of this species with bluish or
cream-splashed
leaves. The Swiss-cheese or shotgun philodendron (P. friedrichsthalii)
has elongated leaves, on a vine to about 6 feet, that are riddled with
irregular holes.
Perhaps the most common
philodendron, and one of the most common houseplants, the heart-leaf or
vining-hearts philodendron (P.
scandens oxycardium) also is a vining
type. It has heart-shaped, olive green
leaves, and is very adaptable to a range of indoor conditions including
low
light. 'Micans' or the velvet
philodendron is a form of this species with velvety green leaves above,
and a
dark copper color below. Similar but with larger leaves is the cultivar
'Miduhoi'. 'Aureum' is a form with
lemon-lime leaf color. 'Medio Pictum' has green leaves with a wide lime
central
streak. 'Variegatum' has green leaves streaked with gray green and
cream.
Similar but with more elongated, heart-shaped green leaves is 'Burle
Marx'.
A few upright species are
tree-like, or "arborescent", and are generally too large for most
interiors. The Lacy-tree or formerly
Selloum philodendron (P.
bipinnatifidum) is an example, getting up to
15
feet in the wild, although the cultivar 'Hope' is much lower and
suitable for
indoors. 'Xanadu' is a popular hybrid,
originally from Australia, which looks like a smaller 3-foot tall
version of
this species in a birds-nest shape. You may even find a golden form of
this.
Other philodendrons are upright,
and if the leaves are so closely spaced to not see the stem they are
called
"self-heading". One species in
this group is the red bristle philodendron (P. squamiferum) with deeply
lobed leaves up to 18-inches long that are a medium green with red
bristles on
leaf stems. The palmleaf philodendron (P.
pinnatifidum) species has metallic green lobed leaves, with leaf
stems
red-spotted. Similar but faster growing,
and a more glossy and deep green is 'Florida Beauty'. Mamei is a
species with wide, pleated leaves
and silvery spots.
Self-heading types with light
orange waxy leaves include the cultivars 'Autumn' and 'Prince of
Orange'. These
need high light for the best color.
Green-leaved self-heading cultivars include the deep green 'Green
Emerald', the bright green 'Emerald Duke' or 'Imperial Green',
'Moonlight'
starting yellow then turning to green with age, and the waxy green
'Wind-Imbe'. There are quite a few
self-heading cultivars with reddish black leaves including 'Burgundy'
with
reddish leaves and dark veins, the dark 'Black Cardinal', the deep red
'Imperial Red', 'Red Emerald' starting deep red and then turning dark
green,
and the similar but lobed 'Red Empress'.
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