Orchid Culture - 2016 Questions & Answers
by Sue Bottom, from the St. Augustine Orchid Society Newsletter.
Email us with any orchid question, if we can't answer it we'll find someone who can! Send photographs too!
Sunburn on Dendrobium
Q. Would you know what is happening to my Den. spectabile? This has been extremely healthy until now.
A. That is the evil sunburn. The changing light in the spring and fall can cause previously happy orchids to be exposed to much higher light levels. The white scar on the leaf means the chlorophyll was bleached out, but not quite burned badly enough to turn black. All growers sunburn an orchid or two each year, despite their best efforts.
Yellowing Leaves on Dendrobium
Q. When I bought this Den. chrysocrepis they told me to dip it in water twice a week. I sprayed it with peroxide for bacterial brown spot but it looks worse every day. Why are the leaves turning yellow?
A. First, water rather than dip your plants. Bacterial brown spot usually starts as a small sunken spot that later expands and can be surrounded by a yellow halo. I suspect there is neither a bacterial nor a fungal problem, it may just be losing its leaves in anticipation of a coolish dryish winter.
I am not familiar with this plant so I looked it up. It must be pretty rare cause it's not listed in Lavarack's book on dendrobiums. The Baker's culture advice in OrchidWiz suggest it is a fairly high elevation plant that likes cooler nights, not a good sign for us here! The Bakers talk of it doing well mounted, with lots of water in the spring and summer and then a cooler drier winter. I have no idea if it goes dormant or semidormant in winter or whether it normally drops its leaves. Given the little bit of into I can find out about it, perhaps you should contact the vendor you bought it from and see if they can give you any advice.
Brown Spots on Phalaenopsis
Q. I noticed some brown streaks on the underside of my orchid. It is the only leaf that has it right now. Could it be getting burnt on the bottom? Or is it mold?
A. That plant looks very very happy, don't change a thing! I'm guessing the spotting is just pigmentation, perhaps the changing sun angle means it was getting a little more light on that portion of the leaf and the pigmentation is sort of like a suntan. The plant looks very healthy, and looks like it should be in bloom in a couple of months!
Yellowing Pseudobulbs on Nobile Dendrobium
Q. The Den. Yellow Canary Song has awfully yellow pseudobulbs. Is this normal, or the result of too much rain or too much sun? Several other nobile types also display this yellowing.
A. As long as the tissue doesn’t feel softer than normal, I think it will be fine. There is no sign of rot. My initial reaction is that they've been getting lots of sun, they look healthy other than color and maybe that just means they stored away plenty of energy for blooming next spring. As long as the canes feel normal, I wouldn't change anything you’re doing.
Circular Rings on Dendrobium
Q. This phalaenopsis type dendrobium has circular rings on one of the leaves. It gets indirect sunlight all day on a southern veranda and is never kept wet, in fact the plant seems dehydrated. It doesn't quite look like anything I've seen on the internet, but I fear it is virused. Could it hopefully be something else?
It has been growing great roots, even put out 7 flowers for me this year!
A. I don't like those rings any more than you do, but it may not be virus, it could be some sort of fungus extending out from a central point. It doesn't look like it's on the other leaves, so perhaps you should just remove this leaf and watch it. If you think the plant is dehydrated, it probably is. Dendrobiums can take a lot of water during the growing season. (Nov-16)
Black Spots on Dendrobium
Q. Do these black spots spell the doom for this Dendrobium Frosty Dawn?
A. That leaf is toast. Those little bacterial spots can be treated with hydrogen peroxide, it works on plant bacteria too! If you remove the infected tissue and spray or pour peroxide over the rest, it should stop the disease from spreading. The rest of the plant looks fine. (Nov-16)
Mushrooms Growing in Potting Mix
Q. I have discovered these small mushroom-like things growing in the dirt with my orchid. I've had this orchid in the same dirt and pot for 2 yrs and never had them before. What should I do?
A. Repot immediately! Your mix is rotting, that's why the sporing body of the fungus (the mushroom) has appeared on the top of your mix. When you knock the plant out of the pot, I suspect you will see that your roots are also rotting.
Water Filled Leaf
Q. I came home from work today and noticed the bottom leaf was yellow/green and was filled with a liquid, then it fell off of the orchid. I last checked the orchid yesterday, and didn't notice anything wrong. My orchids sit on my indoor ledge, and I have the curtains opened for them to get sunlight. What next?
A. That is bacterial soft rot caused by Erwinia (now called Pectobacterium). Immediately remove the leaf, spray or drench the leaves with peroxide, consider spraying with a copper compound. It is a very fast moving bacterial rot that will kill the plant if it reaches the crown. It moves very quickly and can kill a plant in one or two days.
Separate Keikis from Vanda
Q. I have a very large vanda orchid that has three medium sized keikis. I got the mother plant 2 years ago when it was in bloom. Since then it has produced no new leaves or flower spikes. This seems unusual to me because all my other vandas are constantly producing a new leaf or flower spike. However, it easily produced these 3 keikis, which are thriving. I am concerned that the mother plant may be spending all its energy on the keikis and not on its own growth, since its leaves look a dark dull green, whereas the keikis are bright green and healthy. I would like to remove the top keiki, which now has 15 leaves and is about 15" tall, but it has no roots. What do you suggest? I keep waiting for the keiki to produce roots, but none thus far. I took pictures of the plant some time ago, but the keikis are nearly twice this big now.
A. I would not remove the top keiki, with no roots it will simply perish. The keiki should have at least three roots to be able to sustain itself before separating it from the mother plant, and some folks believe the keiki should also bloom before separation as a sign of its maturity.
With the three keikis growing and the mother plant treading water, I wonder if your plant isn't telling you that its survival and its future are in the keikis. More than once I have cut away the mother plant leaving the keikis in the bottom of the basket to grow up and bloom, and either given the mother plant away or tied it to a hook. It often seems that the keikis are healthier, happier and more attractive than the mother plant.
If you were to cut away the mother plant, check out the stem as an indication of its health, looking to see if it has become woody (is dying) or if it has the red band around the edges (has fusarium which is blocking the vascular tissue).
Yellow Rings on Phalaenopsis
Q. I sent you these pics of the top and bottom of my phal leaves, and you suggested I test them for virus. It started with small yellow spots and the lab has confirmed that it is Cymbidium Mosaic Virus. I’m thinking of throwing away the plants showing severe symptoms of orchid virus. I think the virus was spread through spider mites. What shall I do with the rest, the good looking orchids?
A. I'm sorry about your plants, those yellow rings are unlike any 'normal' phal disease I have seen. The first thing to do is make sure that you don't spread any disease from plant to plant, so wash your hands after touching plants, use a single edged razor or sterilized cutting tool to cut spikes or roots while repotting, etc. Here’s a link to some sanitation guidelines.
The CyMV doesn't usually cause color break so the decision to keep or throw away becomes a personal one. I don't like looking at plants that are obviously diseased so if I were in your shoes I would throw them away. Then just watch the others. Miticides containing the active ingredient abamectin are effective for mites.
Sunken Black Spots on Cattleya
Q. What do you think is wrong with this orchid. The Agdia test for virus was negative.
A. With the sunken spots, it looks more like a bacterial than a viral problem, possibly bacterial brown spot from Pseudomonas, now called Acidovorax. That leaf is pretty severely damaged so you might as well remove it and consider spraying with a bactericide.
Rotten Pseudobulbs on Miltonia
Q. I have a Miltonia spectabilis with rot at the base of several of the pseudobulbs. I sprayed it with Physan and then drenched it with peroxide. Now I guess I had better remove the affected bulbs and further treat with Dithane and cinnamon, too. It has bloomed in July the previous two years so when it didn’t bloom, I started examining it closely and found scale as well as this rot.
A. I think you may have to put on your scrubs and break out the scalpel. That brown line working its way up the pseudobulb looks like black rot to me, caused by one of the water molds that thrives in wet conditions. You have to cut away all affected tissue. Where it is visible at the base of the pseudobulb it has likely already travelled up the pseudobulb and it will die within a matter of days. You have to cut back along the rhizome until you don't see any discolored tissue in either the base of the bulbs or the rhizome.
Then, take whatever you have left and water blast it to remove all the papery sheaths and the scale hiding underneath the papery sheath. Then we'll see what you have left of the plant, whether to put in an empty clay pot and mist daily til you see new roots or a very small pot with a little sphagnum. Black rot is fast and deadly. Dryness and peroxide will help. Only the very expensive fungicides labelled for pythium and phytophthora will really put a hurt on the water molds.
Resituate Oncidium so Roots Grow Into Mix
Q. This Aliceara Memoria Jay Yamada was a much
larger plant. It had some problems with rotting pseudobulbs last
year so I removed them and fitted the orchid into its current pot. It now
looks like this. Any recommendations?
A. The new growths are starting to throw off new roots, but they are several inches above the potting mix so it will be difficult to stabilize the plant. Perhaps you should consider resituting the plant so the roots can grow directly into the medium. New roots are starting now so it would be a perfect time to repot it and let it reestablish itself.
Zygopetalum Potting Mix
Q. I am fairly new to orchid growing and am reading
everything I can find. So far I have 3 lovely Phalaenopsis that are doing well.
Today I bought a mystery plant at the grocery store and am hoping you can help
identify it. It has large pseudobulbs, and has very tall and slender leaves. It
stands about 22” tall. The flowers are kind of a wine color edged in green.
Also, it seems to be potted in regular soil. I am planning on removing most
and re-potting in bark mix. Do you think this is a good plan?
A. That is a zygopetalum hybrid, beautiful and fragrant. It is probably potted in a soilless mix, a peat based mixture with perlite,
which is just fine for these guys. Let it bloom and don't even think about moving it to bark. As long as the plant is not wobbly in the pot, your plant has well established roots. Most orchids like to be tight in the pot, but if you find the roots are so voluminous in the pot, you can simply drop it into the next size pot and backfill around the root ball so you won't disrupt the roots. Quite nice!
Bought Unusual Orchid at Redland Festival
Q. I got this Kefersteinia tolimensis from a Colombian grower at the Redland Festival. I repotted it in a mix of fine bark, perlite and tree fern fiber in a 3" clay pot. It is growing under my lanai roof with a ceiling fan for air movement but, of course it has been extremely humid recently. I assume it has a fungus?
A. I'm not familiar with this orchid so I looked it up in OrchidWiz and what's there does not bode well for us being able to grow it well in Florida. The Bakers say it grows at elevations of over 1500 meters and summer highs are 72 to 77F with nights of 57F! They also say it requires very strong air movement, likes lots of water, hates to have the roots disturbed, does better on a mount or open basket and likes shady conditions, 1200 to 1800 foot candles, around phalaenopsis light. You got it from one of the South American growers, so it is also suffering from transplant shock, transportation shock, and the seasons being 6 months out of whack after changing hemispheres, so I'd say you have your work cut out for you!
The first step is to stabilize the plant and stop the bacteria from spreading. If peroxide doesn't stop the enlargement, you could try one of the copper compounds. Then think about where you can put it to mirror some of its natural habitat conditions. A nice shady spot will help keep it cooler during the day. Do you grow anything mounted? Perhaps mount it or put it into an open basket with just a little long fibered NZ moss to help with cooling and root moisture. You may also think about bringing it into the house during the hottest months to keep it a little cooler. You have lots of things to consider.
White Smut on Cattleyas
Q. My problem seems to be with Cattleyas and I call it White Smut. It cleans up with alcohol but the damage is done and it comes back. I’ve talked with people and they seem to say it’s mealy bugs but I don’t believe that is the case. I seldom see any mealy bugs around my plants but what do I know. When you magnify the picture it has a strange form. I’ve lost flowers due to the deterioration of the sheath. What do you call it and what is the remedy?
A. That white smut is scale, boisduval scale to be exact and it is the bane of every cattleya grower on this Earth. It is on the base of the pseudobulbs, on the rhizome between pseudobulbs, sometimes the leaf axils, under leaves, roots, you name it. That black scarring is the damage from the scale. I had scale for years and years until I tried the insect growth regulator Distance. Distance will not kill scale, but it will prevent the scale from moulting so juveniles will never be parents (expensive though about $180 a quart).
You have to apply it with something that will kill the adult kill scale, one of the imidacloprid products are relatively cheap or the broad spectrum Safari (again expensive). Pestrong.com has the best prices. You might have to find another cattleya grower or three to split the cost with, but scale can be eradicated. You can suppress the population with alcohol, but you will not kill it. Until you get the Distance cocktail, buy one of the systemic insecticides and apply it as a drench so it will be absorbed by the roots upward into the plant. By the next day, you should be able to flick the scale off with your finger. I actually use a hose with a nozzle sprayer set on flat and water blast the dead remains of scale off plants. Scale is public enemy number 1 to the cattleya grower!
Spines on Orchid
Q. Do you know if these are spines on this orchid?
A. I've seen these growth aberrations on plants from time to time, they are not spines, just extra tissue. I have no idea what causes it, Courtney thinks perhaps some plants have a genetic predisposition to form them. No worries.
White Bugs in Drainage Saucer
Q. My orchids are doing fine, they have strong leaves and good roots. But when I water them there are small white bugs that appear in the water. Leaves, stems and aerial roots all seem OK. Only on one of them I found something looking cottony, so I took it out of the pot but I didn't find anything unusual.
Taking it out, I left the bark in water and the little white bugs do come out also.
A. Look closely at those roots, you can see lots of mealybugs feeding on them. Take the plants to the sink or outside use a hose with a hose end sprayer and blast the roots to physically remove the mealybugs. Then pot them back up and pour a systemic insecticidal drench through the pot, double strength because mealybugs are really tough to get rid of.
White Balls in Potting Mix
Q. I noticed that my phalaenopsis flower buds have been drying up and falling off before or slightly after blooming. When inspecting them, I lifted the bark and discovered these things growing under the lop layer. Yikes! Is it some sort of mold or pest?
A. That looks an awful lot like snow mold, that grows on decaying bark and will smother your roots. You should repot your orchid pronto into fresh mix, and wash the roots thoroughly to remove any snow mold spores that might be on them.
My Orchid Has No Leaves
Q. Can you tell me why my orchid looks like this? It has pretty much looked this way since I bought it from my Orchid Society, it may have had white blooms. I grow it the same as my other orchids and they are all great. Once a month I fertilize, I water very little and mist the air. It gets bright light but no direct sun.
A. That looks like one of the soft caned dendrobiums. I think the tag says Den. Sea Marian 'Snow King' which is one of the Dendrobium section Dendrobiums, commonly referred to as the nobile group. This type of dendrobrium goes semi-dormant during the winter months when you water maybe twice a month and let it get cool to say into the 40’s and then it flowers profusely in the spring. During the growing season you water and fertilize it like mad. It has very definite seasonal growth patterns. You can read about how to care for different types of dendrobiums under cultural requirements.
I'm not sure what you mean when you say you water little and mist the air. I’m gathering you’re growing inside in a northern climate. As a rule, when you water you should water well and then not water again until the plant needs more water. Misting is okay to supply humidity but it doesn’t have the same benefit as watering the roots.
Q. What is going on with this orchid?
A. I suspect that you have mites. To confirm, get a magnifying glass and look at the underside of the leaf or take a kleenex and wipe the underleaf and see if you see reddish brownish smudges. If you do,
that’s mite poop. Take the plants to the sink, wash top and bottom leaves with soapy water, then spray with straight isopropyl alcohol. Walgreen’s sells it in a little sprayer that is very handy, I keep one in my growing area. Do this for any plant close to the infected one, and you’ll probably have to repeat weekly for a month or so.
The plant is stressed right now, so let it stay a little drier and when you start to see new root growth you can repot.
Multiple Phals in Pot
Q. I bought this plant for a friend at the Jacksonville show 5 or 6 years ago. There were 2 plants at that time. When I repotted it about 4 years ago, I could only see 2 plants iin the pot. Now there are 4 blooming spikes from 4 different sets of monopodial leaves. There are 2 and maybe 3 sets of leaves that do not have spikes.
I do not know if phals branch or 'fork' on same set of roots so I don't know for sure how many plants are in pot. Roots that are visible look great.
I am challenged with the decision to repot and separate or leave it be. Obviously my friend has taken great care of it.
A. I would leave it all in the same pot, so as to get the best show of flowers possible. If it needs to be repotted, you can just leave the plant together when you situate it in its new home. Phals are monopodial as you know so they grow upwards rather than horizontally along a rhizome so they don't fork or branch. Some easily form new plantlets from adventitious tissue in the stem of the plant, called basal keikis. This plant looks like a very fertile Myrtle and should reward with tons of flowers.
Black Spots on Schomburgkia Hybrid
Q. Please look at the two photos of leaves on a Schomburkgia Wellesley.
New leaves are quite clean with a few tiny black spots.
Old leaves have black areas. Perhaps they started out as spots and grew into bigger areas.
The flowers have no deformities.
The old leaf looks like your photos of Guignardia and Cymbidium Mosaic Virus.
Which one do you think that it is?
A. To know that the two images are from the same plant is kind of amazing. From the first image, I would say virused and the second image makes me think not so much. I really think there are times when you just have to bite the bullet and get the test strips so you can be sure. I test some and throw away about $10 on plants I know are virused and then there are those that you think are virused and they test clean. Courtney’s advice is really the most practical. If there is color break, toss the plant. If it has a poor growth habit and you can’t make it grow better, toss it whether it tests positive for virus or not. If it is virused and perhaps ugly but the flowers are not impaired, you may decide to keep it, just make sure you practice good hygiene when handling plants. Those plants with ORSV are the ones that most often show color break, and many times those with just CyMV show no defect in the flower.
I’d say it’s unlikely that it is guignardia, very possible that it is virused. Then you have to make the philosophical decisions whether you want to test to be sure and then whether you’re willing to toss or keep virused plants in your collection. Best of luck deciding which way you want to go! (May-16)
Dark Purple Pseudobulbs
Q. I bought this Epc. Charlie Brown last September. He bloomed but didn't have many roots. I repotted and sprayed the roots weekly as they started to grow at the top. I didn't water thoroughly since there were not many good roots, if any, in the medium. Once in a while I watered the pot. Now I see that the older pseudobulbs have turned a dark purple or black. Is this black rot and was it caused by overwatering? Is there anything I can do to save this plant, I really love this orchid.
A. I don’t think that’s black rot, it’s not soft is it? I’m guessing the discoloration is a response to sun and/or cold. Try adding a little Epsom salts when you’re watering and fertilizing, maybe add 1/4 tsp Epsom salts/gallon. That will provide extra magnesium and improve greening.
After you repot you can top dress with a little sphagnum moss to provide a extra moisture around the new roots, this is more effective than misting the roots. Spraying is no substitute for a thorough watering. When you water, water heavily so the media is wet through and through. (May-16)
Orchid Root Tip is Black
Q. My orchids have attached themselves nicely to this tree branch and have good healthy blooms coming along. They get watered and fed regularly when we are here, then pretty much fend for themselves over the summer. However, yesterday I noticed that the tips of the roots are turning black. What does this mean?
A. Is that root really black or is it just starting to grow? If in fact the tip does turn black and die, you would think it would be salt toxicity, but I wonder if it is just waking up and starting to grow again. I think they’re fine. If they start looking dead, we’ll come up with Plan B.
Q. After searching the web for a site to help me identify a recent orchid purchase in south Florida, I stumbled upon your site. Little did I know, my search brought me home, here in St. Augustine. The tag said simply, "rare orchid". The leaves are different from the only other orchid I have in that they are longer and some with translucent. Can you help me identify it?
A. Small world, isn't it! That could be a Phaius tankervilleae, known as the Nun's Orchid, or one of its hybrids. It probably came from George Hausermann of EFG Orchids in Deland, and he can give you a positive ID if you want to be sure.
By the way, I noticed some white spotting on the leaves, perhaps you should take a close look at them to make sure there is no scale on it. It sure looks like it is going to put on a great show for you!
Phal Spike Growing Back onto Itself
Q. Have you ever seen anything like this? Our first stem of the flowering season seemingly grew back into itself! Will the stem grow and bloom if we cut it?
A. I have seen this on one or two plants each year. Sometimes the spike is growing around a leaf and gets twisted around itself. I have tried to very gently unkink the spike and usually have ended up breaking it with my attempt to fix it. Now if unsuccessful after one or two gentle attempts at reorienting it, I just let it do what it wants to do. Ultimately the spike will grow upward reaching for the sun and you may end of with a shorter spike, but it will flower and next year should flower normally. If you cut it, your chances of the stem continuing to grow and bloom are slim.
Q. I've been growing orchids for well over 50 years and most of my experience has been with epiphytes. My lone terrestrial, Habenaria medusa, was recently unpotted. Then I read your article, and now I realize that I took no note of the growing end. Which end should be up and which down?
A. What a beautiful tuber, or should I say tubers! The top of the tuber is where the two tubers join together. You can see where the bottom of the tuber flattened a little bit when it reached the bottom of the pot. The tubers look really healthy, bet you got a great flower or two from it this past year. You can pot them in either a ProMix soilless mix or in sphagnum moss, then wait for the new growth to begin before watering. Find a nice shady spot and keep them moist while in active growth and look forward to the fall show.
Pock Marks on Phalaenopsis
Q. My phal has pock marks on its beautiful petals but the leaves are untouched and very beautiful.
I bought it from Home Depot in great condition and the condition developed 2 weeks afterwards.
A. That looks like botrytis on the flowers, a fungal blighting that ruins the flowers but doesn’t really hurt the plant. You can spray it with Daconil or use the home remedy of baking soda, 1/2 tsp dissolved in 1 quart of water sprayed on the flowers. The spots will likely remain for the life of the flower, so it is best to remove the flowers to prevent spreading the disease.
Black Mark on Blue Phalaenopsis
Q. I noticed this morning that the stem of my orchid is turning black and I can't seem to find anything on what it might be, any ideas?
A. Your phalaenopsis was injected with a dye to turn the flower color blue from its normal white. If you look down the flower spike , you’ll be able to find the injection point. The black isn’t black really, it’s the discoloration from the point of injection where they dyed the flower. It won’t hurt the plant. Enjoy the blue flowers this year. If you can, summer it outdoors in a shady spot protected from the rain, let it get a little chill this fall and then bring it inside to a nice warm spot.
Next year when it reblooms, it will bloom white and you might even enjoy those white flowers more!
Soft Rot on Phal
Q. I got this plant last month. In looking at the pictures on your great site, I decided this is brown rot. I immediately cut off the infected areas and sprayed with a copper fungicide (which I cannot believe I have). Tomorrow I will spray the green house with this fungicide. Am I on the right track?
A. No question, bacterial soft rot, and it moves very fast leaving water soaked leaves in its wake. You were right to remove the entire leaf and copper was the best choice of chemicals to treat the sanitized plant. Paphs and phals seem to need more protection from winter rots than other types of orchids. The only problem with copper is that you can’t spray anything in bloom cause the flowers will die, also no dendrobiums cause they’re sensitive to it and even some thin leaved genera may not like it.
Check your greenhouse to see if there’s any evidence of rot in your other plants, but I’m guessing the plant got stressed or too cold or something during the time it was moved from its warm growing greenhouse to yours, although if you have some place in the greenhouse where condensation can drip on your plants or if water stays too long on leaf surfaces, that can lead to rot too.
Winter Watering of Catasetums
Q. I got six Catasetums from Sunset Valley Orchids in September. They have not flowered yet and still have green leaves. I am watering them sparingly. Shall I totally stop watering them?
I have attached a photo (took it this morning) so that you know their current condition.
I have grown Cycnoches (just one) with success in the past but have never grown Catasetum.
A. Most people now advise encouraging catasetums to go dormant by withholding water by December, though the earlier orchid advice said just cut back on water to maybe every two weeks until the leaves start to yellow and die. I think you’ve got some really nice seedlings that may or may not go dormant.
I would follow the old advice and water them twice a month as long as the leaves are green. You probably don’t have to worry about repotting them this year cause there is plenty of room left in the pot plus Fred uses high quality sphagnum and packs it very very tight. I usually knock them out of the small 2 inch pot that Fred ships them in and drop them into a small clay pot, sometimes with a peanut or two in the bottom or just an air space and let them grow another year. Next winter you can repot them. They are not going to flower for you this year (unless there is clowesia in the breeding). They look good!
Q. I have a little coconut orchid I bought a few months ago. I repotted my plant and pruned its roots so that the dead roots wouldn't rot. It's in fir bark, perlite, charcoal, and sphagnum. The house is fairly dry due to forced air heat. It sits on a pedestal in a large east windowsill. I mist the plant a few times every day to increase humidity. It gets watered about once per week. What am I doing wrong?
A. The roots need to regrow before anything else will happen. I’d add another inch or so of sphagnum to the top of the pot and increase the watering, maybe to twice a week this time of year. That bark is pretty chunky and the mix may not be holding enough moisture. You may think about a cool mist humidifier to increase the humidity rather than misting the plant. See if you can find a sunnier spot that will also be warmer during the day, a south window perhaps?
Before we knew it, the individual wrote back to us: Based on what you said, I decided to be a little drastic with this orchid. I have to get proper water for my cool mist humidifier, but in the meantime I moved it to the bathroom for heavy humidity, added warmth, and additional light options. There is also good air flow there. I figured since the roots were probably all dead I'd just repot it again with a greater ratio of sphagnum and smaller fir bark. I mixed the medias with a little cinnamon to help ward off fungus and mold. I also wet the media so it was damp when I repotted the little guy. I gave the orchid more moss on the top like you said. The plant looks better already!
Dark Spots on Tips of Mature Cattleyas
Q. I have a frustrating leaf spot problem in which clusters of dark spots appear typically on the underneath tip of the leaf of my mature cattleyas. This problem is new in my collection, occurring just in the past year. I have treated with Banrot but the the problem persists. I grow on NE facing screened pool cage, use MSU type fertilizer and monthly add physan to control fungus. Have you seen this and do you have any suggestions for treatment?
A. The spots are isolated and sunken which suggests a bacterial infection like bacterial brown spot, in which case copper is your friend. Bacterial brown spot can affect older cattleya leaves but in mature plants it is slowly progressing.
Your worst fear would be that it is viral, so rule out virus first. Assuming it's not virus, apply an antibacterial. There are fancier antibacterials like Zerotol, but copper is tried and true as long as you avoid dendrobiums and some of the thin leaved genera that may be sensitive to it.
If it’s widespread in your collection, then you may have to think about how you could change your growing conditions so conditions aren't favorable for bacteria. If it is just here and there and it really bothers you, break out the razor blades and remove the source of infection although each cut would introduces a pathway for more pathogens.
Vanilla Orchid Won't Bloom
Q. I have a vanilla orchid that I bought 10 to 15 years ago. When I got it, it was growing on sterile medium and was about an inch tall. I brought it home, planted it in regular potting soil and it grew great. At one point the stems with leaves were 10 to 15 feet long, but it never gave any sign of blooming. It finally got so big that I took some cuttings from it, and gave the large plant to a friend with more room. The cuttings are doing fine, but why can't I get it to bloom? It gets sun 3 to 6 hours a day depending on the season and I've tried no direct sun. Any suggestions?
A. Vanilla has to be really big to bloom, say about 2 inches in circumference minimum. I also wonder whether it would get enough light indoors to bloom. It looks like it is growing next to a very happy african violet, and these are typically low light plants. I had my vanilla in a greenhouse and it finally got big enough to bloom but it also decided to take over the greenhouse space. So I gave the pieces away to a new home to make room for something that would bloom more easily in the allotted space.
Bifoliate Cattleyas Potted Too Deep
Q. I have a Cattleya Chongkolnee 'Kayla' HCC/AOS (bowringiana x Chocolate Drop), I know it has bifoliates as parents. What causes some of the pseudobulbs to have two leaves while others only have one? I also have two bifoliates I'm struggling with that came to me being potted too deep in their medium. I'd love to repot them but I know it's not the right time of year. These two plants also have a fungal problem. Question is, should I take my chances and repot during the wrong time of year with a sick plant in hopes to "fix it" or leave it be until spring?
A. The C. Chongkolnee has all bifoliate parents so I can’t imagine why some have single leaves and some double. Usually when a bifoliate hybrid has single leaves, it’s because there is a unifoliate somewhere in the parentage, but that isn’t the case in your plant. I suppose it’s possible the second leaf got damaged and fell off, look closely at the apex of the pseudobulb and see if you can see where a second leaf used to be attached.
I think I’d be inclined to wait until new roots are beginning to show on the bifoliates before repotting, and it may be summer rather than spring. You can also just knock out the top layer of potting mix without disturbing the roots. That one Portia x labiata has some rough leaves. I think I’d remove that most damaged leaf, and if you want to spray something, copper is a very good, cheap and effective fungicide and bactericide, just don’t spray it on dendrobiums or something in bloom.