How to Grow an Arrowhead

Support

• The arrowhead plant has a vining growth habit and can reach a height of 3 to 6 feet when mature. Outdoors, it can climb a mailbox post or fence. When grown as a houseplant, it needs staking in its pot, either with a trellis or another type of support. It can also adhere to a moss-covered pole or stake. You could also grow it in a basket as a hanging plant, with the vines cascading over the rim of the pot, but its vines can become quite long and may need heading back from time to time to control the plant's size when grown this way.

Light

• The arrowhead plant is also called the goosefoot plant because of the shape of its leaves, which are triangular when young but become divided or lobed when mature. Growing it in bright, indirect light produces strong, bushy vines, but you should protect the plant from direct sun, which can scorch its foliage. Outdoors, an ideal spot gets an hour or two of morning sun, followed by light shade for the rest of the day. When grown indoors as a houseplant, it does well under artificial lights or placed 1 or 2 feet away from a curtained south- or west-facing window.

Soil and Water

• The arrowhead plant does best in an organically rich, well-draining soil mix. You can use any commercial houseplant potting mix or make your own mixture from 2 parts loam, 2 parts peat moss and 1 part sand or perlite. Outdoors, the plant tolerates any soil that's well-draining. If your soil contains clay and tends to hold water, add some sand to improve its drainage, while adding some compost can increase its fertility. The plant prefers even, regular moisture. Water a houseplant when the top 1 to 2 inches of soil feel dry, and provide extra water during dry spells to a plant grown outdoors or water it whenever the soil stays dry for a few days.

Fertilizing and Problems

• An arrowhead plant does well when fertilized every two or three months with a balanced, 10-10-10 fertilizer, diluted at a rate of 1/4 teaspoon per 1 gallon of water. When grown indoors, low humidity can cause leaf margins to become dry and brittle, a situation you can improve by misting the plant every day or two. It can also attract spider mites, especially in dry indoor air. These and other soft-bodied pests, such as aphids, can be controlled by spraying with insecticidal soap, diluted at a rate of 5 tablespoons per 1 gallon of water. All parts of the arrowhead plant contain a toxic substance that can cause severe mouth pain and should never be eaten by people or pets.