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Orchid Care 101 Glossary
This is a work in progress. If you have a suggestion of a word or phrase that needs explanation please e-mail. We are not planning for this to include all orchid words, just the most common that a newcomer might hear.
- active eye
All pseudobulbs, even old leafless pseudobulbs, have eyes located at the base. At the beginning of a new growth cycle, one eye, usually on the youngest pseudobulb, becomes an active eye. As it activates the eye forms a tab that grows larger and pulls away from the base of the pseudobulb, which soon becomes a pseudobulb, itself. At the same time, new green tipped roots form.
Ants are a threat to your orchids. Yes, it is a major annoyance when ants boil out of a pot in protest when you water 'their' orchid, but ants are more of a problem than a simple annoyance. Ants bring with them both aphids and mealy bugs. Ants will actually carry them around and place them on your plants. You cannot get rid of mealy bugs and aphids without first getting rid of ants. There are good products readily available for ants. The ants among the orchids are the sweet eating variety. Put out lots of ant stakes and traps. I put out a new batch twice a year.
Back bulbs are the old generations of growth that have been removed from an orchid. Each growth cycle, (often a year) new growth comes from the youngest pseudobulb. The past generations look dormant, even dead, but they are an important part of the plant. A plant will not bloom without 3 to 5 connected pseudobulbs. If the newer part of the plant is damaged or removed, the older parts will come out of dormancy and begin active growth.
Sometimes long, thin pseudobulbs are referred to as canes. The only difference between a pseudobulb and a cane is the shape. A cane functions in the same way as a rounder looking pseudobulb. Pseudobulb shape is an important identifying characteristic.
An epiphyte grows attached to trees. They are neither symbiotic nor parasitic; they are just looking for a place to grow without getting their feet wet. Generally speaking, assume that an orchid is an epiphyte unless it is identified as Lithophyte or Terrestrial.
- growth habit
Growth habit refers to many characteristics of the orchid, but it is often used in a more limited way. In advertising you may see the phrase compact growth habit. This means that the rhizome is short and the pseudobulb is not real large. This is generally desirable in a houseplant. How it grows, seasons, temperature, light and water requirements are all part of the growth habit.
When an orchid is under stress some species of orchid will go through a process know as "throwing a kiki". Dendrobiums are particularly prone to this, sometimes for no apparent reason. Phalaeonopsis will usually grow a kiki on a flower spike. A kiki is genetically identical to the parent plant. It is not a seedling and will often bloom within a year or two. After the roots of the kiki are an inch or more long, it can be removed from the parent plant and grown separately. You can tell the difference between a kiki and a new growth. The new growth is attached to a rhizome and a kiki attaches in random places on a cane or an old flower spike.
Inflorescence is the same as the more common term flower spike. It refers to the whole flower structure, not just the flowers themselves. Where and when the spike occurs varies from variety to variety and is important to know.
- leaf axil
A leaf axil is the point at which the leaf connects to the stem or the pseudobulb. This is where the action is. The thing to remember here is that the leaf axil tends to collect water. If water is allowed to sit in the axil when the temperature drops at night, it may get a bacterial infection and die. This is especially true of Phalaenopsis. This is a condition called crown rot that can kill the plant in two or three days. If water gets into the axil, you can use a paper towel to wick out the water. This is the reason for the guidance to only water before noon.
- mealy bug
Mealy bugs are relatively common pests. They are difficult to eradicate because of their protective outer covering. Mealy bugs are sap sucking insects which feed by puncturing the surface of the leaf. Mealy bugs are covered with a waxy, whitish substance. They are clearly visible to the naked eye. They are transported by ants. You cannot get rid of them until you get rid of ants. To kill mealy bugs on an individual plant, a q-tip dipped in rubbing alcohol works well. I also use a spray filled with half strength rubbing alcohol. I spray all over the area. After a few seconds, I spray with plain water to wash away both the alcohol and bugs. Look at the plant every day and repeat until no more are found. Often there will be no more after the second day.
- monopodial grower
Monopodial means 'one foot'. A monopodial grower refers to a plant that has no pseudobulb. Since it lacks the storage capacity of a plant with a pseudobulb, they need more even watering. Leaves grow one at a time on top of the previous leaf. The plant grows taller and taller. Flowers and new roots grow from the leaf axil moving slowly up the plant as it slowly grows. Phalaenopsis and Vanda (pictured) are common monopodial growers. Plants with pseudobulbs are called sympodial growers.
Pseudobulb means litteraly 'False bulb'. Looking at some orchids it is easy to see a part that reminds us of a bulb. Long, thin pseudobulbs are referred to as canes. Plants with pseudobulbs are called sympodial growers. Assume that an orchid has a pseudobulb unless it described as a monopodial grower. The pseudobulb has the same function as the barrel of a cactus; it holds water and nutrients. If you were to cut one open you would see the same type of flesh as a cactus and water would squeeze out of it when crushed.
The rhizome is a fibrous connector between pseudobulbs. In good conditions, water and nutrients flow through it from the new growth to the older growth. When conditions are bad, they flow toward the new growth to keep it strong enough to survive. Orchids are divided into two or more plants by cutting the rhizome. A very successful tactic is to cut the rhizome in the pot without disturbing the plant in any other way. When the plant is repotted after a couple of months both parts will be stronger and healthier than if the dividing and repotting were done at the same time. The length and thickness of the rhizome is a big factor in the orchid's growth habit. When the rhizome is especially long, it is known as a travelling rhizome. Sometimes a rhizome grows not only out but up. Both of these ways of growing makes it hard to keep a plant confined to their pot.
Roots in orchids serve the same general purpose as in all plants, to collect water and nutrients. The root is a thin, wiry thread surrounded by a layer of velamen. Roots only grow from a new pseudobulb. The roots of older pseudobulbs become less and less effective as they get older. For monopodial growers such as Phalaenopsis and Vanda, new roots grow from the stem, usually higher than the last root. Sometimes a plant has gone through a time when growing conditions are not good during a growth cycle. Then not much growth happens during that time and the plant conserves energy. If conditions improve a new growth will be triggered and some of the older roots from the previous cycle will develop a new green tip and continue the growth that was interrupted earlier. This is a very good sign that the plant is happy and is more likely to bloom.
For orchids that have no leaves at the base of the pseudobulb, the flower spike forms in a sheath at the top of the pseudobulb. Among these are Laelia, Cattleya and Encyclia. When the spike forms it can usually be seen inside the sheath. However, the sheath may remain without a spike for quite a long time. Keep an eye on it. If the sheath turns brown before the spike forms, that pseudobulb will not bloom.
Snails and slugs are a problem when growing outside or in a greenhouse. They are very athletic. This snail has made it through a baited obstacle course, scaled a 3 foot wall and overcame an 8 inch overhang to get to this tray full of mounted Phals inside a greenhouse. Most of the time, however, you will not see the snail or slug. There will be new roots mysteriously missing and maybe a faint slime trail. They attack at night then find a hiding place for the daytime. Get plants off the ground up on benches. Use snail bait on the ground around the plant stands. It is effective but only last for awhile, especially if it is getting wet. Don't use the snail bait on the plant itself except when you think there is a slug hiding inside the pot itself. Inspect the new roots and leaves often for damage.
Velamen is a thick outer coating of from 1 to 24 dead cells on the roots epiphytic of orchids. It absorbs and holds water. The velamen acts much as a sponge when water is present and it contains canals and channels to move the water inward. When a root takes up water velamen turns from white to green. The picture on the right shows the color change only a few seconds after water was sprayed on it. The velamen will turn completely green when wet. When it is touching a surface other than air, young living velamen may form water absorbing root hairs on sides of the root. Actively growing tips are almost always referred to as green tipped roots, but the color is not always green. This root on an Ascocenda is redish. This is not a problem. The growing tip is where the new velamen forms.