Mention the genus Tillandsia to most gardeners, and you get a puzzled look. No, I’m not talking about the eight-legged spider (that the mere mention of its name invokes fear). I said, “Tillandsia,” not tarantula. These plants don’t bite! Even though Tillandsia, the largest genus of the bromeliad family of plants, has several species that resemble the ominous tarantula, rest assured that no harm will come to you by owning these unique plants. Most gardeners and consumers know them by their common name, air plants, and they are not aware of the many variations in size and form, as well as the diverse geographical distribution of these plants.
Tillandsia ionantha is generally the most recognizable species by the general public because it is frequently sold attached to figurines in various chain stores. It is a delightful miniature plant that reaches a height of about 4 inches and grows in dense masses in Mexico, Guatemala and Nicaragua. Characterized by its cluster of silvery rosette leaves that blush a vivid red when beginning to bloom, it produces a tubular purple flower.
Lacking a root system, Tillandsia duratii, native to parts of Argentina, Bolivia and Brazil, improvises by using its modified twisting and contorting leaves and stem to secure itself to a host.
About now you’re probably asking, “What’s so unique about tillandsias?” Well, I’m glad you asked! Tillandsias are indigenous to the southernmost parts of the United States and to South and Central America. They are epiphytes, meaning that they grow nonparasitically upon another surface, deriving their nutrients and water from rain, air, and dust. Varieties can be found growing on trees, rocks, cacti, cliffs and other hosts. The ability to survive without a functional root system contributes to the diversity of these plants. Unlike terrestrial plants, which derive their nutrients and water through their root system, the leaves of Tillandsia have specialized cells called scales or trichomes that allow water and nutrients to be taken in. These trichomes give the plant its silvery-gray, somewhat ashy appearance.
As the plant dries out, the trichomes open to absorb moisture and nutrients. When sufficient hydration has been achieved, the cells close to retain the moisture. The concentration of trichomes on the surface of a plant’s leaf is a good indication of whether the plant is native to a sunny and dry or a humid and shady environment. The sunnier and drier the environment, the greater the concentration of trichomes on the leaf’s surface and the grayer and stiffer the texture of the leaf. The dense concentration of trichomes allows the plant to absorb more moisture and to reflect the harsh effects of the sunlight. The roots of Tillandsia, in most cases, serve only to attach the plant to a host.
Species exist such as T. duratii, a native to Brazil, northern parts of Argentina and Bolivia, which lack a root system. The “duratii” uses modified leaves that twist and curve to secure itself to a host. There are in excess of 550 species of Tillandsia, and very few produce fragrance from their flower. T. duratii belongs to a select group, producing highly fragrant lavender blooms from the ends of its wheat-colored flower stalk.
Most Tillandsias, with a few exceptions, bloom only once in their lifetime. After blooming, “pups” form around the base or from the axil of the “mother” plant. They will eventually mature and complete their blooming cycle in one to several years, depending upon the species and the growing conditions. The quickest way to propagate them is by division. Once the offsets or pups mature somewhat, they may be removed to grow on their own. Attempting to propagate them from seed can be a lengthy (4 to 7 years) process but may prove rewarding to the individual who has the patience to endure.
The common name, air plant, is somewhat of a misnomer. I’ve talked with many individuals whose plants died several months after acquiring them from a retail store, and the single most common factor for the plant’s demise is that they were not watered; with the second reason for decline being lack of adequate lighting. Tillandsias in their natural habitat are able to get all the necessities from the environment to survive, such as moisture, light, oxygen and nutrients, but when taken out of that environment, these elements need to be provided. In other words, when growing your plants indoors, they need more than just “air” to survive.
Water your plants and give them plenty of light and an occasional feeding. Simply misting is generally not a sufficient water supply to sustain them. Give your plants a good “dripping wet” watering at least once a week. Increase your watering frequency as conditions dictate. If you want to increase the bloom and offset (pups) production of your plants, then feed them monthly from March to October with a Bromeliad fertilizer (17-8-22). Other water-soluble fertilizers such as Rapid Grow and Miracle Grow can also be used at half strength.
Tillandsias will tolerate natural, bright indirect sunlight or artificial lighting. If fluorescent lighting is used, it should be located no more than 12 inches from the plants. If you have poor lighting conditions for plant growth in your home or office, there are a host of inexpensive, specially-designed plant lamps that will provide excellent lighting and are available from local retailers and nurseries. The appearance of your plants is the best indication of their particular needs. Generally, plants with soft, green to green gray leaves require high humidity, frequent watering and prefer shaded areas. Plants with stiff, gray to gray-white leaves require brighter light and less watering. All Tillandsias like good air circulation and should be allowed to dry out between waterings. A plant that is constantly wet cannot breathe and will suffocate to death.
Most Tillandsias thrive at temperatures found in most homes. Although many varieties can survive below or above the average range of temperatures, most are tolerable to temperatures ranging from about 50 F to about 90 F. Don’t be afraid to experiment by moving your plants to various growing areas within your home or office and note which location they grow best in. Tillandsias are relatively pest-free, since they do not require soil (the medium where many plant pests reside). The sanitary nature of these plants makes them an excellent choice for hospitals or other areas where a clean, healthy environment must be maintained.
MOUNTING AND DISPLAY
Tillandsia enthusiasts love the unlimited possibilities afforded them for mounting and displaying their plants. Some truly unique arrangements combining Tillandsias with other plants can be achieved. A mount can be as simple as a plant hung by its roots from a piece of fishing line, or for the more adventurous, use a waterproof adhesive to attach plants to a host. Virtually any mount that can withstand frequent watering can be used, but I prefer mounts that have a rough surface like rocks, tree limbs, or driftwood. When these natural mounts cannot be found locally, excellent alternatives that will last a lifetime are those decorative structures made for use in aquariums. Goop, Liquid Nail or even a hot glue adhesive can be used for attaching plants by their roots to a mount. Non-copper wire or nylon fishing line may also be used to hold a plant in place until its natural rooting system takes hold of the substrate.
All can be purchased at most department, hardware and homebuilder stores. Avoid attaching plants by their leaves; they will become detached as the leaves begin to die and wither. When possible, orient plants on their mounts so that excess water will drain from the crevices of its leaves or bulbous base, and avoid attaching plants in the recesses of mounts where excess water cannot drain off. Although it is not necessary to mount your plants to appreciate their beauty, my growing experience has shown that mounted or attached plants outperform unattached plants in growth and hardiness, and mounting enhances their appearance. During seasons where the outdoor temperatures consistently remain above 40 F, plants may be placed out of direct sunlight, in the branches of trees, on patios or attached to other outdoor structures.
Even when not in bloom, the exquisite form of the Tillandsia plant foliage is a thing of beauty. Its bloom should be considered an added bonus for the successful grower of this remarkable and diverse collection of plants.
Can I grow my plant in soil?
There are a few species of Tillandsia that are both terrestrial and epiphytic. Always ask your supplier if the plant you are purchasing is in this unique group. Otherwise, placing your plant in soil equals certain death.
Should I remove the bloom spike after it has dried and become unsightly?
I recommend clipping the bloom spike at this point. Doing so will not harm the plant and will channel the nutrients absorbed by the bloom spike to other parts of the plant.
Can the roots be trimmed?
The roots can be trimmed without causing any harm to the plant. In most instances, no nutrients are derived through the roots, and they only serve to anchor the plant to a host. They will grow back.
A version of this article appeared in print in Virginia Gardener Volume III Issue III. Photos by Arthur Comer.