Sobennikoffia robusta

June 7, 2007

Hi everyone --

Haven't posted in quite a while. Since moving to the Panhandle of Florida from Vero Beach eighteen months ago, seems like I don't have the time I used to! Orchid collection is still poorly-housed in a makeshift greenhouse...hopefully I can build a better one someday.

Anyway, I purchased six of these Sobennikoffia robusta plants from Malala in 2005. Four remain and are doing well. These were very old plants, and I had to cut several inches off the stems to get the roots down to basket level. It has a really nice, sweet fragrance at night.

Not a common species here in the States. Enjoy!

Bruce C.

Comments (16)

  • clintdawley

    Very cool...They look like vandas, but do they require as much light to bloom?

  • wetfeet101b

    I like the flowers. Very simple yet elegant.

  • thesnowpea

    Elegant blooms indeed. While the foliage is reminiscent of vandas, the blooms somehow bring dendrobiums to mind.

  • randyhi

    Cool!!! Never seen this genus over here. Looks like an angrecoid?


  • bcfromfl

    Hi again --

    Thanks for your thoughts and comments! Yes, it is an angraecoid from Madagascar. It seems to be able to handle somewhat of a range of lighting conditions, from shade to some direct sun. However, the foliage is a bit nicer in shadier conditions, which is how I have them positioned right now...and blooming was no problem.

    As they get larger they can have more bloom spikes, and I saw a photograph once of a specimen that was truly spectacular. I'm pleased how tough these plants are, and how vigorously they grow. Looking forward to seeing them do more and more each season!

    Bruce C.

  • sdahl

    Sure seems to like it there!


  • mrbreeze

    Oh wow...this is probably the greatest post I've ever seen on GW. I'm VERY impressed. Sobenikoffias are perhaps the greatest 'unknown' Ang.

    I have two robustas and one humbertiana. I'm VERY VERY interested in hearing more about how you've been growing yours? I've read that humbert tends to grow as an epiphyte, whereas robusta grows as a terrestrial. I was told by someone that robusta (and perhaps A. sesquipedale and others) should be grown in a potting soil. I'm too paranoid to try that since ...if i kill the plants, I may never get another chance to get more.

    I'm also wondering how you deal with winter rests? I believe it was Hillerman that said you can somewhat ignore that requirement and grow them year round. But again, knowing they come from the west side of the island and normally get a brutal six month dry spell...i'm paranoid about that as well. Any and all culture tips are appreciated SO much, you obviously know what you're doing with them. Thanks for posting and growing them!!!

  • ntgerald

    They are absolutely fabulous.

  • bcfromfl

    Thanks again for all your thoughts and comments!

    Hey Mr.B...according to the book, Angraecoid Orchids by Stewart, Hermans, and Campbell (you need this book -- order it from Amazon), both species are either epiphytic, semi-epiphytic, or lithophytic depending upon whether they are located in humid evergreen forest or dry forest/bush. Humidity and rainfall allow them to take root and grow on tree trunks, otherwise, they need their roots into loose soil or around rocks to find moisture.

    Mine have been among the easiest angraecoids I've ever grown. I have them in six-inch baskets, with a special 60/40 live oak bark/pine bark mix I made up. On the top of the mix I put a layer of that nasty green moss all the Malala plants came packed in and wired to those sponges...you know what I'm talking about. Anyway, I figured there probably was some good mycorrhizal fungus in there.

    Light isn't super-critical, I'd err on the shadier side of things, although I'd describe it as "bright, open shade."

    Because my greenhouse conditions both in Vero Beach (Zone 9b) and here in the Panhandle north of Panama City (Zone 8a) put me at the mercy of outdoor temperatures and humidity, my angraecoids have always naturally entered and stayed in dormancy from November through March. I know there are others who push them year 'round with even moisture and fertilizer, but that's only for those who can maintain temps, I dunno, above 60 or so. My nighttime winter temps regularly dip into the 40s, and even the 30s. There was one night in particular this past December I was really sweatin' it -- despite the fact that my 1500-watt heater was on full blast, I hit a low of 32.7F inside the greenhouse when it dropped to 20F outside!!! With temps that low, plants MUST be kept on the dry side, otherwise, you'll be left with mush. I didn't have a single casualty in my collection from the cold. I think what saved me is the fact that when the sun comes up over the trees at 6:30-7am or so it hits the side of the gh quickly bringing temps back up into the 70s and 80s.

    I ventilate as well as I can, but my hanging plants (closer to the ceiling/roof) have to withstand 100-110F daily highs from May through October, from 11am until 3pm. Running my misters will drop temps a little, but not significantly. Plus, I can't just run and run the water, or I'll drown things. Don't have space for an under-bench system. Eventually if/when I can build a better gh it will have a dedicated 2000 cfm chiller.

    During the warmer months I water daily as needed. Usually I just turn the misters on for a 5-minute spritz, other times I'll give my plants a 20-minute drench. If I drench one day, I might wait a few days to do it again depending upon how warm and dry the air is I'm pulling through the gh. As you can tell, my gh is a "seat-of-the-pants" operation, and the only thing on a timer is the exhaust fan (not enough cash right now for a decent thermostat).

    I used to be a "weakly, weekly" fertilize-er, but I'm too busy and distracted these days to keep track. From April through October I give my entire collection full-strength 1 tbsp. per gallon every two to four weeks. I use the cheap MiracleGro African Violet Food (7-7-7 with micronutrients) that comes in the purple 8-ounce bottle, around $2 from WalMart. Let's see...two tablespoons per ounce, so each bottle makes 16 gallons. Takes two gallons to fertilize my collection, so each bottle lasts a good long time.

    That's about all I can think of. Nothing extraordinary, other than a good dose of several types of mycorrhizal fungus (of unknown benefit) from the moss and live oak bark.

    Hope this helps!

    Bruce C.

    P.S. My Aerangis verdickii has two long developing spikes -- hope I can protect it from the roaches!

  • mrbreeze

    Hey thanks Bruce! I really appreciate the tips. I think I've been growing mine too dry in general. A lot of my plants don't spend enough time in a growth phase, probably due to bad conditions in the house. Last year one robusta that had been dormant since I got it in 2005, finally woke up when our temps got over 100. It promptly went right back to sleep though. Have you thought about pollinating a flower or two? It would be great to see babies in the states. Malala may never come back. :(

    Congrats on the verdickii. Mine is still too young. Kill the roaches!!! I think they're in the squirrel family.

    Oh, how often do you water them in the winter? thanks again.

  • bcfromfl

    Sounds strange about your plant -- it shouldn't have been dormant for a year like that. I think your idea about the watering is probably a valid one. A whole lot has been written and discussed on the Forum about humidity over the years, with most saying things like they grow their phalaenopsis on the windowsill in low humidity just fine. But with mounted plants, or those in baskets, humidity is really key -- it allows the velamen on the roots to stay in optimum growing state by maintaining a proper moisture level without constantly watering.

    I think I saw a pic of your setup once upon a time, and you should have decent humidity, so I'm not sure what to suggest. The sobennikoffias are really "root-intensive", if that makes sense. The root growth on this genus is pretty phenomenal, so if you're not seeing root growth, you need to look at your conditions and make adjustments. Similarly, if your plant wakes up then quickly goes dormant again, something is missing in the equation...

    I probably will do flasks at some point, but I won't do a selfing. I'll wait until next year, when I anticipate my other plants will be blooming as well. Four plants isn't really enough to do selection for flower variations, but I've got some good solid stock, so the progeny should be pretty good.

    I watch the humidity in the winter to be my guide for watering. Here in the Panhandle, both 2006 and 2007 saw heavy rains in January and part of February. This kept humidity up there enough that I may have skipped watering for a couple weeks at a time. But February was also cold for days on end, so I had to watch the timing carefully, watering in the morning when the gh heated up but with enough hours for excess to evaporate before night. (I had to remember to take out the electric heater before turning on the water -- forgot a couple of times I watered so infrequently!)

    Things dry out so quickly in general in my gh that I don't have to worry too much about rot. If my humidity was better, I'd have to be more careful. I'd say a good rule of thumb for winter watering is to give them enough to avoid leaves from beginning to shrivel, and root tips green/yellow depending on the species.

    But your collection may not go into a winter rest. If not, you may be able to water more frequently. You're going to have to watch leaf and root growth to be your guide. Angraecoids are seasonal growers of course, but if you're still seeing marginal growth I'd treat it like it wants to grow, and not rest.

    There are some really fascinating photos in the book I mentioned, that shed a tremendous amount of light on culture. A picture's worth a thousand words! One photo is of an Angcm. rutenbergianum in bloom growing on a rock outcrop on the top of a mountain. I can imagine the cool winds and sunshine during the day, drying off the heavy overnight dews. Several photos of aerangis species in situ -- one in particular is of Aer. kotschyana growing on a small tree with a trunk perhaps three inches in diameter. It would take a tremendous amount of rainfall and humidity for a plant like that to live on a relatively small tree. Another photo showing Aer. confusa, and another with Aer. kirkii demonstrate the same thing. One of my goals someday is to have a gh that I can grow plants like the ones in this book -- with multiple growths and dozens of spikes!

    The more I know about this hobby, the more I am amazed how identical plants can grow so differently for different people, under different growing conditions. You'll have to trust your eyeball for the best feedback on how to grow your babies. If, in the case of your robusta, something's obviously not right, maybe you can change pot/mount/basket, or something with the mix, or...


  • ifraser25

    Not a common species anywhere I should think. It's amazing how after 15 years of growing orchids you still keep coming across new ones. Congratulations!

  • claritamaria

    Excuse me for butting in but this post is indeed very interesting. After I posted on another thread to Mr B about a sleeping plant I got curious as to why my Ang Elissii is sleeping, along with another vandaceous type. I got on the Baker's sheets and started gross analysis. Both plants are in decent light, humidity never gets below 65% and they venture outdoors many times a week. So what's missing?

    bcfromfl said it, he has heat. He also has a decent diurnal range. That was also my conclusion looking through the Baker's. I don't have enough heat and possibly range is off a bit. Right now in my conditions are still rather cool. Low 70's average days.

    Having light does not necessarily mean one has heat. Look at what your post says about briefly waking up. It was hot.... I am not wondering if that is the missing piece of the equation for you and me Mr B? Growing indoors does not mean that if the light is good, the heat will also be the same, at least not indoors.


  • bcfromfl

    By chance do you mean Aerangis ellisii? This species is found from 3,000 to 6,000 feet in elevation, classifying it as an intermediate grower. While the low 70s may be a bit on the cool side, you definitely won't get great results above 83F or so. Actually, most angraecoids prefer temps on the cooler side of things, although the low altitude species will tolerate higher temps. I can certainly provide the "short list" of angraecoids that will tolerate above 95!

    For those of you growing under lights, sometimes your temperature gauge isn't telling you everything. Some grow lights put out quite a bit in the far red wavelengths, and your leaf temperature may be higher than the air temperature, from the radiant heat effect. This would give the plant a proper growing temp even if the air isn't quite warm enough.

    Also, 65% humidity is OK, but a better range would be 75 to 85% -- even higher at night. The trick when they're growing is to keep the humidity as high as possible to cut down on evaporation, allowing them to stay damp at the roots for long periods of time. This applies more to mounted plants than potted ones. I've never seen a potted aerangis species thrive, even though you would think that the pot provides more even and constant moisture.

    Hope this helps.


  • mrbreeze

    Oh it helps. There's more info. in this thread about Sob. culture than all the books combined, IMO.

    It is very frustrating to finally have a plant wake up after being exposed to Oklahoma heat for a couple months, only to have it shut down when it comes inside to the AC. Another issue I've had that I'm just recently figuring out, is that I run an oscillating fan 24/7. I do it for air flow but moreso, to move the vapor from my humidifier around and to disperse the mist from the nozzles. If I didn't have the fan on, only certain places would get drenched and others would go bone dry. However the down side is that it dries things out too quickly and disperses heat. The solution is for me to get a greenhouse or sunroom.

    My humbertiana seems to really like living in a clay pot with diatomite media.

    I've had similar problems with various forms of A. ellisii starting roots and then stopping too early. One thing I've tried that does seem to help is to drape live spanish moss around the mounted plants, especially the roots that hang down.

    Keep up the good work Bruce! The Anglican force is strong in you...

  • Judybird2014

    so glad I found this, long time..
    Mr. B, don'tcha love all that info from THE man!!
    Bruce has helped me so many times thru the yrs,
    a super teacher GW is fortunate to have around!

    FABulous pic, B, my orchid bud~

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