There’s a reason why tillandsias are called air plants. Just don’t call them airheads.
You may have seen an air plant hanging in an open-faced glass vase or hanging from a seashell at your local garden center. They are becoming popular. Air plants are easy to grow if you follow a few rules – and easy to kill if you don’t. Air plants may be sold with the hype that they live on nothing but air, but this is not the case.
First, what is an air plant? Air plants are in the bromeliad family. The air plant genus Tillandsia (tih-LAND-zee-ah) is the largest in the bromeliad family. The names tillandsia and air plant are often used synonymously and many affectionately call them Tillys. There are a couple of major differences between tillandsias and the other bromeliads. Most bromeliads have tightly fitting leaves that hold water in a reservoir at the center of the plant. Many tillandsias also have this “rosette” shape, but care must be taken because if water is retained too long in the center of the plant, it can cause the plant to rot and die.
Most bromeliads grow as “normal” plants with water-absorbing roots in the ground or on a host. Tillys use their holdfast roots to anchor themselves in place, water is absorbed: through their leaves, not their roots, with few exceptions.
Air plants are epiphytes like many bromeliads, tropical ferns, orchids and Christmas cacti. An epiphyte is a plant that is anchored to another plant or object that is called the host. The host only supplies a perch, but no nutrients. Spanish moss is a tillandsia that is common in the Southern states and is often seen hanging from host trees, telephone wires, fences and the occasional light pole.
You can successfully grow air plants in your house without roots. They can be attached to bark, rocks or other household decorations with wire, glue or Velcro. Or you can set one down in a sunny place where you think it looks best.
Tillandsias are native to the warm and temperate areas from the southeastern United States through Mexico and down through all of South America. There are different species that are native from coastal areas all the way up to mountainous elevations more than 9,000 feet high. Some are native to forests, and many grow among cacti and on rocks or on sand in deserts.
The air plant leaf is covered in scales or hairs called trichomes that act as sponges to quickly absorb water when it becomes available. For the species exposed to more sunlight, the trichomes also reflect up to 70 percent of the sunlight that strikes the leaves. Tillandsias that are native to drier xeric climates have larger, denser and often feathery trichomes covering the leaves. Tilly leaves in wetter mesic climates are often smooth and look transparent, but they are still covered with trichomes.
Most tillandsias follow the same basic form, having leaves that emanate from a central axis and then gradually tapering to a point. However, some leaves can be short and spikey while others can be long and curly. Some are bright green while others are covered with the white, fuzzy trichomes. Many look a lot like the leafy top of a pineapple plant, which is no surprise when you know that both air plants and pineapples are types of bromeliads. They range in mature size from just 1 inch to more than 3 feet across.
When many tillandsias bloom, the leaves turn red or pink to attract hummingbirds, their natural pollinators. They send out a flower stalk that can be two to three times the length of the leaves. The stalk is usually brightly colored. The tube-shaped flowers attract hummingbirds. Some tillandsia flowers are very fragrant and attract moths or butterflies. The colored leaves and inflorescences can last for weeks. Each flower generally lasts for a day but a number of tillandsia inflorescences produce many flowers over a month or two.
Tillandsias are easy to hybridize. Rainforest Flora, Inc. from Southern California has created several hundred over the years. But the main way they reproduce for most of us is by producing offsets, or pups, after blooming. As the pups reach about half the size of the mother plant, they can be separated. However, by leaving them together, they will eventually grow into a gorgeous clump that will have multiple inflorescences at the same time.
How to Grow Tillandsias
Paul Isley III, president of Rainforest Flora, says, “Indoors, place them close to a sunny window, but make sure that they only get direct light for an hour or two at a time. Southern exposure is great, but watch the amount of direct sunlight they get. Xeric (drier growing) tillandsias that usually have stiffer, harder leaves and a more pronounced covering of white trichomes will do better with more sun than the softer, greener leaved tillandsias.”
Outdoors in the summer, bright shade is best. A little direct sunlight is usually fine. When the weather begins to turn, bring your air plants indoors. The best times are those few weeks when you don’t have to use either the air conditioner or the furnace.
Indoor watering is normally easy, according to Isley. “Using a container that has a lid, collect rain water. Submerge the air plant every week for several seconds, take it out and turn it upside down for a few seconds so water can’t collect in the base, which can cause the plant to rot, and put it back. If the tilly is getting good light, that should be enough unless the air is unusually dry, as it often is when central heating or air conditioning is used. In this case, try to have some other plants or other water source around to add a bit to the humidity. If the leaf edges ever begin to curl up toward each other more than normal, this is a sign of dehydration – the plants wasn’t receiving enough water frequently enough. The solution is to submerge the plant in the “good” water overnight. This will cause it to completely rehydrate if it hasn’t dried out too much.”
Keep water for your tillys in a tub with a lid to prevent it from getting dusty and evaporating. You can use this same water until it runs out. I like using a gallon plastic ice cream container for my smaller tillandsias and a 15-gallon storage containerfor the bigger plants that are mounted on large pieces of wood or bark. I collect snow in the winter but, of course, I don’t use it until the water has warmed to room temperature. If the plant is blooming, don’t dunk the flowers under water.
Outdoors, tillandsias just need a quick spray from the hose. Once the leaf is wet, more water isn’t needed. Just be careful not to water the xeric tillandsias too often since they don’t need it.
Isley says, “Fertilizing tillandsias is also easy. In fact, if you put a quarter teaspoon/gallon ratio of Epiphytes Delight or Miracle Gro in your dipping/soaking tub, your fertilizing task is done! You can use other fertilizers but the key is to make sure that the nitrogen component has ammoniacal and nitrate nitrogen. The urea-based nitrogen in most commercial fertilizers needs bacteria in soil to break it down so that plants can use it. Tillandsias don’t have soil, so the urea nitrogen isn’t broken down and is wasted.”
Tillandsias make beautiful architectural accents anywhere in the house. No matter where they are normally placed for best growth, they can be easily moved to a new location for decorating purposes. “In normal conditions, you can put a tillandsia pretty much wherever you want for a month or so with no permanent harm to the plant, but eventually they want to receive bright light and sufficient water,” Isley says. “Many people rotate their plants on a monthly basis so that they can have them where they will look the best but not necessarily grow the best.”
The most definitive book on tillandsias is Tillandsia II by Paul T. Isley III. This coffee table-sized book is filled with hundreds of color photos and covers the biographical history of how tillandsias were discovered and propagated.
Also from Paul T. Isley III, “The Genus Tillandsia” is a fact-filled 28-page booklet with many gorgeous color photos for those who would like an introduction to these remarkable plants.
Air Plants by Zenaida Sengo is not just a book about growing tillandsias. It covers many beautiful ways to incorporate them into the design of your indoor landscape, including several craft ideas, such as Christmas wreaths.
A version of this article appeared in Chicagoland Gardening Volume 22 Number 2.
Photography courtesy of Jeff Rugg.