From the tropical Americas. Fast-growing plants that are nearly indestructiblecan be grown well even by those who manage to kill everything else. Plants are favored for attractive, leathery, usually glossy leaves. In good conditions, old plants may bloom; flowers resemble those of calla (Zantedeschia), with a boatlike bract surrounding a club-shaped structure. Bracts are usually greenish, white, or reddish. Browsing deer don't seem to care for these plants.
Philodendrons fall into two main classes.
Arborescent; relatively hardy. These are large, shrub-size plants with big leaves and sturdy, self-supporting trunks. They can be grown indoors but need much more space than most houseplants. They grow outdoors in the Coastal and Tropical South (USDA 9-11). As landscape plants, they do best in sun (some shade at midday where light is intense) but can take considerable shade. Use them for tropical effects or as massive silhouettes against walls or glass. Excellent in large containers; very effective near swimming pools.
Vining and self-heading; tender. This class includes tender plants of two different habits. They can grow outdoors only in the Tropical South (USDA 10-11), where they require partial or full shade; elsewhere, they are houseplants. Many kinds are sold, with many different leaf shapes and sizes. Self-heading types form short, broad plants with leaves radiating out from a central point. Vining types do not really climb and must be tied to or leaned against a support until they eventually shape themselves to it. The support can be almost anything, but certain water- absorbent columns (sections of tree fern stem, wire and sphagnum totem poles, slabs of bark) serve especially well, since they can be kept moist.
The following list indicates the class of each species and selection. Note that one popular philodendronthe so-called split-leaf philodendronbelongs to another genus, Monstera.
P. bipinnatifidum (P. selloum). Arborescent. Treelike shrub to 615 ft. high and wide, typically with a single upright trunk that leans with age. Deeply cut leaves to 3 ft. long, on equally long stalks. 'Hope' is a compact shrub to 4 ft. high and wide and is reported to be hardier than the species.
P. domesticum. Vining. Often sold as P. 'Hastatum'. Grows to 1020 ft. high, with arrow-shaped, bright green leaves to 2 ft. long and 1 ft. wide.
P. erubescens. Vining. Often sold as P. 'Hastatum'. To 1020 ft. high, with foot-long, arrow-shaped, deep green leaves with coppery undersides. Subject to leaf spot in overly warm, moist conditions. A number of selections and hybrids are available; they are more resistant to leaf spot and tend to be more compact. Some, possibly hybrids, have much red in new foliage and in leafstalks. 'Royal Queen' has bright red new growth; mature leaves are dark green heavily tinged with red. 'Emerald Queen' is a choice deep green form. 'Pink Princess' has shiny black to deep burgundy leaves splashed and speckled with white and pink. Best color in bright light.
P. 'Hastatum'. See P. domesticum, P. erubescens
P. hybrids. 'Lynette' is self-heading to 1 ft. high, 2 ft. wide. Makes a tight cluster of foot-long, broadish, bright green leaves that are strongly patterned by deeply sunken veins. Good tabletop plant. 'Xanadu' is self-heading and grows 3 ft. high and 5 ft. wide with large, drooping, glossy, green, deeply lobed leaves. 'Autumn' is self-heading, grows 2 ft. high and wide with colorful leaves that emerge coppery red then go through shades of red, orange, and yellow before maturing to shiny green. 'Cobra' is a climber with oval leaves variegated and spotted with white.
P. martianum. Self-heading. To 2 ft. tall, 34 ft. wide. Leathery, lance-shaped, dark green leaves grow to 1 ft. long and 68 in. wide; each leaf has a broad midrib and a swollen-looking, spongy, deeply channeled leafstalk to 15 in. long. Makes a nice coarse-leafed ground cover.
P. melanochrysum. BLACK-GOLD PHILODENDRON. Vining. To 1020 ft. high, with velvety, lance-shaped greenish black leaves to 3 ft. long, 1 ft. wide. Midribs and lateral veins are pale green. The new leaves are heart shaped and have a coppery tinge.
P. scandens. HEART-LEAF PHILODENDRON. Vining. Among the most common philodendrons. Can reach 50 ft. Deep green, heart-shaped leaves; juvenile leaves are 46 in. long, while mature ones can grow to 1 ft. long. P. s. micans has velvety young leaves; mature leaves are smooth. P. s. oxycardium (often sold as P. oxycardium or P. cordatum) has glossy leaves throughout its life. Juvenile forms of both are most popular; they are grown on tree trunks, in hanging baskets and window boxes, as houseplants. Indoors, train them on string or wire for a variety of decorative effects; or grow on moisture-retentive columns.
P. wendlandii. Self-heading. To 1 ft. high, 2 ft. wide. Compact clusters of 12 or more deep green, foot-long, broadly lance-shaped leaves on short, broad stalks. Indoors, this species is useful where a tough, compact foliage plant is needed.
P. williamsii. Arborescent. Arrow-shaped, glossy, deep green leaves to 2 ft. long and 1 ft. wide. Leafstalks almost as long as leaves.
Whether grown in containers or open ground, all philodendrons need rich, loose, well-drained soil. Feed lightly and frequently for good growth and color. Clean dust from leaves of indoor plants. Most philodendronsespecially those grown in containerstend to drop their lower leaves, leaving a bare stem. Once a plant gets gangly and overgrown, the best course is often simply to discard it and replace it with a new plant. However, you can also cut the plant back to short stub, then let it regrow; or you can air-layer the leafy top, then plant the layer once it roots (and discard the parent). Some philodendrons send down aerial roots. Push these into soil or cut them off (removing them won't hurt plant).