Angraecum leonis

Monday, November 18, 2013

Growing Aerangis Species & Hybrids

     Over the last thirteen years growing Angraecoids I have learned that when something works well, don't change it.  But; I also want to know what my parameters are.  Then of course I try to push the envelop by experimenting with different cultures.  Giving my presentations to various societies, I usually talk about Angraecoids that are relatively easy to grow for the beginner.  Gain some confidence and then start thinking about plants that may take a bit more understanding to grow them into fantastic specimens.
     Over the last two years I have posted articles on three Aerangis (Aergs. articulata, Aergs. biloba and Aergs citrata); of which I would consider easy to grow.  This post will deal with several species that I consider easier to grow than others.  As you will see, the culture of many of these plants can be very similar and some with a wide range of culture parameters/variables.  Whether it be a species or a hybrid, cultures can be similar.

Image 1 - Aerangis Mire (Aergs. ellisii X Aergs. verdickii)
     First thing that you should keep in mind is the individual plant's natural habitat.  Take the time to do a bit of research.  Having a basic understanding of the plant's requirements should prevent severe mistakes.  Talk to someone who is growing the plant at the present time and pick their brain.  Learning about a plant's climate, including annual monthly rainfall totals and seasonal temperatures; what is it growing on and the type of light it receives at various times of the year should put you in the proper place. 
     The cultures that I talk about in this post are the cultures I use to grow my Aerangis.  I will make comments regarding the cultures that should be considered in cooler/different climates compared to here in South Florida.  These should be looked at as guidelines or starting points.  What works for me may be different for you.
     There are usually about seventy Aerangis species; but it is not uncommon that a plant or two does get reclassified.  Plant size can range from a near non-existent stem to a stem that can reach a height of 31 inches (80cm) in cultivation (Aergs. ellisii, the seed parent of Aergs. Mire in Image 1).  My present Aerangis collection contains Aergs. hyaloides, a stem that would barely be 1 inch (2cm) to the lengthy Aergs. articulata with a stem that can reach 12 inches (30cm).  There are numerous other Aerangis in the collection at various lengths.
 Image 2 - Aergs. articulata, Aergs. biloba & Aergs. citrata
     All Aerangis as other plants have a wet and a dry season.  These seasons may vary in length depending upon location.  During the wet season, usually the active growing season, many of these plants will flourish quite rapidly.  Aergs. articulata, mystacidii, kotschyana, X primulina and somalensis to name of few of mine will grow considerably fast being exposed to moisture all day and can handle being damp during the evening.  Here in South Florida, the rainy season is heavy and the plants take advantage of the large amounts of water.  Late spring into early fall, temperatures can be in the upper 80s to mid 90s daily.  My mounted Aerangis are watered 2 - 3 times a day and often misted very late in the afternoon.  Roots that are attached to the mount as well as the aerial roots will dry out by the air movement that surrounds them (Image 3).  They are then watered again with this process being a daily regiment as long as the temperatures stay high and the plant is actively growing.
     This much water can start to cause an issue with fungus.  Watch for any brown or black spots on the leaves.  When temperatures do begin to drop, plants will still need moisture.  The combination of moisture and cooler temps, fungus can rear its ugly head rather quickly.  My collection is treated on a monthly basis with a systemic fungicide.  I alternate between Thyomil and Dithane 45 every two - three months, keeping a spray bottle of Physan 20 (a topical fungicide) handily available.
                                                            Image 3 - Aerangis articulata
     Many of the Aerangis can be grown under lights, although they are usually some of the smaller variety such as Aergs. citrata, decaryana, fastuosa, modesta, mystacidii, hyaloides and luteo-alba var. rhodosticta to name a few.  While under lights, these Aerangis should receive about the same amount of water but you must make sure that the root systems are receiving a fair amount of air movement.  When seasonal temperatures begin to drop and active growing has slowed down considerably, watering should be cut back.  Do not let the plants stay dry for extended lengths of time.  If you start seeing wrinkled or withered roots; they are not getting near enough water.  Water them at least twice a week.
     For those that are growing them on window sills or on tables next to windows during the colder winter months; have your plants setting in or very near humidity trays.  When your home or apartment is being heated during the cold winters of the north, humidity drops much lower than the plant is exposed to in its natural habitat.  For small mounted plants, arrange the plants on some sort of a stand so that it is in very close proximity or directly above the tray.  Small pots can be set in the tray resting on glass marbles or anything that can keep the pot above the water line.      
      As mentioned, the majority of my Aerangis collection is mounted.  Some of the larger Aerangis can be grown in pots or baskets as long as a coarse medium is used to allow for fast drainage, good air flow and room for root development.  A good sampling of larger plants for potting would include Aergs. articulata, cryptodon, ellisii, fuscata and kotschyana.  Because these plants produce somewhat pendulous inflorescence, they can be hung on a slight angle so that the spikes can drop over the edge of the pot and flower freely.
Image 4 - Aergs. decaryana X Aergs. mystacidii & Aergs. mystacidii
     Flower shapes of the various Aerangis species that I grow will range in shape from a flock of birds in flight to various star shapes and sizes to unusual fan shapes (Images 2 & 4).  Their sizes vary from flowers that are less than a half an inch (8mm) wide by less than a half an inch (8mm) long and a spur that is club shaped and only 1/4 inch (6mm) long [Aergs. hyaloides] to flowers that are up to 2 3/4 inches (7.4cm) wide by 2 3/4 inches (7.4cm) long with a spur that can reach 5 - 6 inches (12.7-13cm) long [Aergs. articulata].  Colors are white while some of them may have delicate hints of green, yellow or pink at the tips of their sepals and petals.  Spurs will be white, a very pale green or a very subdued yellowish green.
     These are just a few of the Aerangis species that I am presently growing.  As stated earlier, the culture that I am currently using is what works best for me in the South Florida climate.  Do the research and ask questions and you will grow these plants successfully.  They will become wonderful specimen plants.  There will be future posts regarding Aerangis punctata culture as well as a post dealing with the flower shape of Aerangis luteo-alba var. rhodosticta.
     Don't hesitate to ask/post questions or comments to the blog!