The name Philodendron is known to almost everyone familiar with interior plants, but only knowledgeable nursery growers and interiorscapers know the diversity within the 250 or so species that comprise the genus. Although the genus name means "tree lover" in Latin and many Philodendron species are herbaceous tree climbing vines, the genus also includes woody-stemmed plants that may reach 15 feet in height. Native to tropical regions of North, South, and Central America, Philodendron plants have been used in interiorscapes since the 1880s. The genus can be divided into three groups: vining, self-heading, and erect or tree-like. Leaves of the three groups exhibit great variability. Some species have small, heart-shaped leaves while others have large lobed leaves that may exceed 4 feet in length. In addition to great differences in leaf size, leaves of recently developed cultivars vary in color from dark red-black to light orange. The diversity in leaf shape, size, color, and growth habit makes Philodendron cultivars suitable for use as desk plants, hanging baskets, totems, or floor plants. This article describes common Philodendron species and cultivars in the foliage plant industry (See Table 1), provides guidelines on their culture and interior use, and lists physiological problems encountered in both production and in the interiorscape (See Table 3).
Credit: Jianjun Chen, UF/IFAS
Cultural Guidelines
Propagation
Commercially, most named self-heading Philodendron plants are propagated via tissue culture. Philodendron scandens oxycardium is normally propagated using 1–1½ inch stem cuttings with a node and an attached leaf. Buds break in 3–5 weeks and rooting occurs in 4–6 weeks. If larger leafed cuttings are desired for totems, stock plants are grown on a pole or similar support and tip cuttings are used. The tree philodendrons, P. bipinnatifidum and P. selloum, and some of the self-heading philodendrons may be propagated using commercially packaged seed. Viability is very limited unless the seed is properly processed and vacuum-packed. Successful seed germination and early seedling growth require specially equipped facilities, and most plant finishers buy seedlings from propagation specialists.
Production
Sphagnum peat, pine bark, vermiculite, or perlite can be volumetrically combined to formulate media for most container sizes. Three-foot and taller totems should have 10–20% coarse sand to keep plants from wind tipping. Media should have good moisture holding capacity and aeration, soluble salts of 1–2 dS/m, and a pH of 6.0 to 6.5.
Philodendron plants should be grown in a shadehouse with temperatures between 70 and 90°F and a relative humidity of 60 to 100%. Plant quality and growth rates begin to decline when day temperatures routinely exceed 95°F or night temperatures drop below 65°F. Controlled-release or water-soluble fertilizers or a combination of both can be used for Philodendron production. Use a fertilizer with an N:P:K ratio of 3:1:2 or 3:1:3. The suggested application rate is 3 lb N per 1,000 sq. ft per month. Table 2 provides a guide for determining if philodendrons are appropriately fertilized based on leaf analysis.
The plants listed in Table 1, excluding P. selloum, should be grown with shade levels of 80–88% (1500–2500 fc) to produce the best plants for interiorscapes. Philodendron selloum should be grown under 40–76% shade (3000–5000 fc).
Shipping and Interior Care
Philodendrons should be shipped at a temperature of 55–65°F. Once plants are placed indoors, it is advisable not to re-pot or fertilize for about four weeks because plants do not need additional stresses. Plants should not be fertilized if soluble salts are 2.0 dS/m or more. If soluble salt levels are higher than 3.0 dS/m, percolation of media with water may help reduce potential leaf necrosis or damage to the root system. For best growth indoors, media should be kept moist. Most philodendrons will tolerate light levels as low as 75 fc but light levels of 150 fc or more will maintain color and leaf size. Temperatures of 70 to 80°F are recommended.