Arrowhead vine (syngonium)

About Arrowhead vine (syngonium)

Arrowhead vine is a tropical climber from Mexico to South America whose young leaves are arrow- or heart-shaped, often marked with silver, cream or pink, and change with age into big leaves split into 5-11 fingers (NC State). Young plants stay bushy, then send out climbing stems; cut those off to keep it compact, or give it a pole to climb (NC State, Illinois Extension). Outdoors in central and south Florida it escapes into woods and is listed as a Category I invasive, so keep it in a pot there (UF/IFAS, FLEPPC).

Hardy outdoors only in zones 10-12 (NC State), and invasive in Florida; it is grown indoors everywhere and can summer outdoors in shade in its pot once nights stay above about 65 F (MU Extension).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Usually bought as a nursery plant or started from a stem cutting; division and layering also work (NC State, Illinois Extension).

Growing it indoors

• Light: Bright indirect light is best (Illinois Extension); it takes dappled light or part shade, but direct hot sun burns or bleaches the leaves (NC State).
• Water: Keep the mix barely moist, watering again when the top of it starts to dry (Illinois Extension; MU Extension lists it as evenly moist). Water until it drains, empty the saucer after an hour, and give a little less in winter when growth slows (MU Extension).
• Humidity: NC State says it thrives in high humidity while Illinois Extension says it copes with drier air; a pebble tray in winter does no harm (MU Extension).
• Temperature: It likes warm rooms; MU Extension gives 65 F as its night temperature, so keep it off cold winter glass and out of drafts.
• Feeding: Feed a complete houseplant fertilizer at label strength about once a month while it is putting out new leaves, and skip feeding in winter when growth stops (MU Extension).
• Repotting: Repot every few years, when roots fill the pot; NC State says you can trim the roots then to keep the plant a manageable size.

Soil

A regular well-drained houseplant potting mix kept lightly moist (Illinois Extension, NC State).

Pot in a regular well-drained houseplant mix in a pot with a drainage hole, with a pole or totem if you want it to climb (Illinois Extension, NC State).

Feeding

• Spring through summer, while new leaves are coming: complete houseplant fertilizer. About once a month at the strength on the label, watering first (MU Extension).
• Winter: none. Skip feeding while no new growth shows (MU Extension).

Don't feed a newly bought plant for its first few weeks, and don't overfeed, which burns roots (MU Extension).

Varieties (4)

NC State Extension names 4 cultivars.

Pests to watch for

Aphids, Mealybugs, Twospotted spider mite, Thrips

Diseases and problems

Bacterial leaf spot, Soft rot

In the kitchen

Safety: Medium-severity poison (NC State): every part holds needle-like calcium oxalate crystals, so chewing it causes pain and swelling of the mouth, tongue and lips, drooling and trouble swallowing, and the sap can give a skin rash. Wear gloves when pruning and keep it away from small children.

Pets: Toxic to dogs, cats and horses (ASPCA, listed as arrow-head vine and nephthytis): insoluble calcium oxalates cause mouth pain and swelling, heavy drooling, trouble swallowing and vomiting (no vomiting in horses).