How to Care for an Arrowhead Plant

Arrowhead plant (Syngonium podophyllum), also sold as arrowhead vine or nephthytis, is a climbing aroid from Mexico, Central America and South America. The plants sold as houseplants are almost always young, bushy plants with arrow-shaped leaves, often patterned with white, silver or pink. Left alone, the plant changes as it matures: stems lengthen and start to climb, and the leaves become lobed and finally split into 5 to 11 leaflets. Much of growing it well is deciding which form you want.

Light

Give it medium to bright indirect light. Clemson Extension suggests an east window or a spot a few feet back from a west window. Clemson adds that a north window also works. NC State warns that direct sun burns or bleaches the foliage.

Light decides how well the variegation holds. Clemson says the patterned types need the brighter end of the range, because in low light they revert to plain green. If new leaves are coming in greener than the old ones, move the plant closer to the window.

Watering

Let the potting mix dry slightly between waterings. Clemson gives that rule, and University of Illinois Extension describes the goal as keeping the soil just barely moist. In practice, push a finger into the mix and water when the top feels dry, then water until it drains from the bottom and empty the saucer.

Clemson reports stem rot on this plant and NC State reports soft rot. Soil that stays soggy is the condition to avoid, so water less often in fall and winter, when it grows slowly and feeding has stopped.

Potting mix and pot

Use a light, airy mix. Clemson recommends equal parts peat moss or coir, vermiculite and perlite, while Illinois says regular potting soil is fine. Any pot needs a drainage hole. Young plants stay compact enough for a pot or hanging basket.

Temperature and humidity

Clemson says it prefers 65 to 75°F and humidity of 50% or higher, but tolerates lower humidity. Sources differ on how much it cares: NC State describes the ideal spot as warm and humid, while Illinois says it grows best in low humidity. Average household conditions suit it, so there is no need for a humidifier unless your air is very dry.

Feeding

Clemson recommends a balanced fertilizer, such as 20-20-20 or 10-10-10, at reduced strength once a month in spring and summer. It is not a heavy feeder. Stop feeding in fall and winter. Clemson advises feeding even less often if you want to keep it in its compact juvenile form or it is growing in low light.

Pruning and training

Decide early whether you want a bushy pot plant or a climber.

To keep the bushy arrowhead form, NC State says to cut off the climbing stems as they begin to develop. Clemson adds that a plant you want to keep juvenile should not be fertilized often. The trimmings can be rooted.

To let it climb, give older plants a moss pole, trellis or bamboo stake, as Clemson suggests, and Illinois recommends a pole or totem for support. Dwarf varieties stay under 2 feet, while standard types can reach 3 to 6 feet tall, according to Clemson.

Repotting

NC State says repotting every few years, and trimming the root system when you do, keeps the plant a manageable size. Do it in spring, as the growing season begins.

Propagation

Stem cuttings are the standard method; Illinois Extension recommends them, and NC State also lists layering and division. UF/IFAS notes it sprouts easily from cuttings, which is also the problem outdoors. Never throw unwanted cuttings or old plants outdoors: UF/IFAS says it has spread in Florida mainly by escaping from gardens and discarded plant material.

Pests and problems

• Leaves turning plain green: not enough light. Move it brighter.
• Burned or bleached patches: direct sun. Move it back from the window.
• Aphids, mealybugs, spider mites: the pests Clemson and NC State list. Inspect leaf undersides and stems and treat early.
• Bacterial leaf spot and bacterial blight: Clemson lists both and NC State lists leaf spot; neither gives specific treatments. Remove badly spotted leaves.
• Stem rot or soft rot at the base: usually soil kept too wet. Let it dry slightly between waterings and check that the pot drains.
• Leggy plant with long stems and changed leaves: normal maturing. Cut back the climbing stems or give them a pole.

Pets and toxicity

Arrowhead plant is toxic. The ASPCA lists it as toxic to dogs, cats and horses because of insoluble calcium oxalate crystals, which cause irritation, pain and swelling of the mouth, tongue and lips, heavy drooling, vomiting and difficulty swallowing. UF/IFAS adds that the sap irritates skin, mouth and eyes, and NC State notes it can cause contact dermatitis, so wear gloves when pruning and wash your hands afterward.

Outdoors, and why not in Florida

NC State rates it hardy in zones 10 through 12 and notes it can be grown as an annual in containers in bright but shady spots. Keep it in a pot.

In Florida, do not plant it in the ground. The UF/IFAS assessment found arrowhead vine to be an invasive threat, the Florida Invasive Species Council lists it as a Category I invasive, and UF/IFAS does not recommend planting it. It was first collected from a Florida natural area in 1966, and it now climbs and weighs down trees and smothers native ground plants; one study found it suppressed native ferns in South Florida. In other frost-free areas, keep it in containers and never dump plant material outdoors.