The beginning of a new year is a perfect time to start thinking about gardening indoors. It is also a great time to learn and think more about gardening vocabulary. As with any vocabulary, you start with the letter A. Many horticulture terms start with the letter “A.” Today, A stands for aroids!
Aroids or arums are members of the Araceae family. The Araceae family is large, with more than 100 genera and 3700 species of mostly sub-tropical monocots. Many species are popular as houseplants, and a few are distinctive landscape plants. This family of plants is diverse with varying mature habits, leaf sizes, shapes, and coloration. Most members of this family have a similar and distinctive inflorescence (cluster of flowers). The inflorescence consists of a spadix and spathe. The spadix is shaped like a rod and often consists of clusters of female flowers near the base and male flowers near the tip. Surrounding the spadix is a leaf-like bract, called a spathe, that is sometimes colorful and showy. The inflorescence may emit distinctly foul odors (Amorphophallus) and/or produce heat (Symplocarpus) in its attempt to attract pollinators.
You have probably seen or grown an aroid. Common aroid houseplants include philodendron, pothos, Chinese evergreen, peace lily, dumb cane, and Swiss cheese plant. Only a few aroids that are grown as houseplants have showy flowers. Peace lily and Anthurium are aroids with showy spathes. Calla lily and Jack-in-the-pulpit are landscape species with showy inflorescences.
Genera grown as houseplants
| Common Name | Genus | Characteristics |
| Chinese Evergreen | Aglaonema | Variegated green and gray leaves; durable houseplant |
| Elephant Ear | Alocasia | Large arrowhead-shaped foliage on tropical or temperate plants |
| Arum | Amorphophallus | Large, often foul-smelling, inflorescence on plants with branched leaves; dormancy required for repeat bloom |
| Anthurium/Flamingo flower | Anthurium | Often brightly colored spathe with arrowhead-shaped leaves; often grown as a cut flower |
| Taro | Colocasia | Elephant ear like leaves with enlarged, sometimes edible, roots |
| Dumb Cane | Dieffenbachia | Large speckled leaves on plants with thick, cane-like stems |
| Devil’s Ivy/Pothos | Epipremnum | Green and gold variegated leaves on vining type plants; durable and easy to grow houseplant |
| Swiss cheese plant | Monstera | Large plant with large dark green leaves that are dissected or contain holes; some direct light preferred |
| Philodendron | Philodendron | Green or variegated leaves on vining type plant; durable and easy to grow houseplant |
| Peace Lily | Spathiphyllum | Dark green or variegated leaves with showy white spathes. |
| ZZ plant/Zanzibar gem | Zamioculcas | Waxy green, dissected leaves on large plants; drought tolerant and durable houseplant |
Care Indoors
Many aroids are grown as houseplants because of their beauty and adaptability to indoor conditions. Most species prefer bright, indirect light. Swiss cheese plant (Monstera) is the exception, as it prefers direct light, but other species in this family cannot tolerate more than a few hours of direct light each day. They usually perform well in North or East facing windows. Room temperatures between 65 and 85F are ideal, while temperatures below 60F can cause damage to the leaves of some species. While landscape species like calla lily (Zantedeschia), caladium (Caladium), and skunk cabbage (Symplocarpus) prefer consistently moist soils, indoor species thrive when allowed to dry out slightly between watering. High humidity is beneficial, especially indoors during the winter months. Most indoor aroids benefit from a light application of fertilizer once or twice during the growing season. Aroids as houseplants also thrive when slightly pot-bound; You can be a bit lazy and not repot plants every year into larger containers.
Aroids are a global family. Arisaema, the genus for Jack-in-the-pulpit, has species native to China, Japan, central Africa, Tibet, Thailand, Malaysia, India, Vietnam, Taiwan, Mexico, and North America (including Iowa). While fewer aroids can be grown outdoors in Iowa, ones like Jack-in-the-pulpit should not be missed!
Genera grown as landscape plants
| Common Name | Genus | Characteristics |
| Jack-in-the-pulpit | Arisaema | Woodland native noted for distinctive spathe/spadix |
| Angel wings/Caladium | Caladium | Tubers grown in shady locations outdoors during the growing season; noted for showy, variegated leaves; will not reliably overwinter outdoors in Iowa. |
| Skunk Cabbage | Symplocarpus | Early blooming, foul-smelling native to wetland areas in North America |
| Calla Lily | Zantedeschia | Colorful and showy trumpet-shaped spathe with green to variegated leaves; often grown as a cut flower; will not reliably overwinter outdoors in Iowa |
When planning your indoor or outdoor garden for 2021, consider growing some of these diverse aroids. If you want to learn more about aroids, check out the podcast on Aroids from In Defense of Plants. Staff from the Missouri Botanic Garden discuss collecting, propagating, maintaining, conserving one of the largest living collections of aroids in the world.
Other A garden vocabulary terms:
Air plants – members of the genus Tillandsia, are epiphytes that grow in air or outside of the soil. Link to All About Air Plants HHPN
Aerate or Aeration - to add air to something. Aeration is a common practice for lawns to allow air and water to penetrate through thatch or compacted soils. Link to lawn aeration HHPN article
Amaryllis – commonly grown bulbous houseplant. Link to Amaryllis publication
Apples – common edible and popular fruit crop in North America. Several cultivars perform nicely in Iowa. Link to Growing Fruit in Iowa publication
Aphids – Pear-shaped, soft-bodied insects come in a variety of colors and suck sap from garden and landscape plants.
Ants – Familiar but widely misunderstood and unappreciated insects that provide several ecological services in the garden and landscape. Link to In Defense of Ants
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on January 8, 2021. The information contained within may not be the most current and accurate depending on when it is accessed.