C. acaule

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Awardless studette
Aug 4, 2007
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Northeast Illinois
I just finished reading another thread started by another new member. C. acaule was a plant that I had somewhat discounted being able to grow here where I live year round because I'm pretty sure I've seen this pink acaule growing in situ on my own property up north and did not believe I could duplicate those conditions down here. Don't ask me if that is the orchid I have up north or not for sure because it is finished blooming by the time school lets out when we go up for a few weeks so in all these years I've only seen them in bloom twice and it was totally fluke I was up there because of deaths in the family in mid May. I have seen both pink and yellow orchids on my property. Anyway, I can't duplicate what's going on up north here where I live year round but I think I might have a chance trying an acaule because I read these comments contributed by Eric Muehlbauer-

As for light, dappled woodland light is the best. I have mine in open oak woods...when the plants first emerge in late April, they have essentially full sun. By bloom, the oaks have leafed out. But keep in mind that oaks offer open shade...lots of patches of sun for varying times during the course of the day. I have heard that for pot culture, a mix of 50:50 sand and milled sphagnum works well...but I have always grown them in my LI soil, even when trying them in pots....Take care, Eric

I'd like to try one plant but I'd like the area I create to be able to accommodate a few should I find I am able to successfully grow these plants. My thoughts are to dig out a small area and to place roofing liner down. Then I could fill the area with the appropriate sand and sphagnum peat. I have the oaks and hickories to provide the dappled shade mentioned by him. Question, should the tube sand (not play sand) be rinsed before added to the hole? Should a few perforations be made in the liner to allow for some drainage?

Note to self to avoid digging around for info in that other thread- "Use ordinary builders sand...not playsand. It must be silica sand...much of the Playsand sold is actually oolitic aragonite, a Ca carbonate compound...certain, probably instant death for acaule."

A member named kentuckiense suggested several nurseries but the first two were sold out as mentioned by the other new member and the third was in Belgium and I am not familiar with them anyway and would not feel comfortable ordering from them. How does one go about getting on a waiting list to purchase plants when a nursery is sold out or how does one go about pre-ordering a year or so in advance? Simply by contacting the nurseries and respectfully asking?

I checked out the site recommended by a member named Rick for availability of acaule. He mentioned http://www.orchidmix.com/cyps.htm
They have acaule in a near bloom size and a bloom size for only $40 and $55 respectively. Is bigger and more mature better when ordering this plant? If I place an order with him would I ask for the plant to be shipped to me in the pot in the event the medium was injected with mycorrhizal fungi as opposed to bare root?

An organization was mentioned by the name of Gore Orchid Conservatory. Do they sell cyps and does anyone have a link to them please?

Next question, I am leery of alleged "salvage" plants. How does one know if plants being sold are actually rescues and not field collected and being sold under the guise of having been salvaged? I wouldn't even consider taking a Cyp from my own property up north for colony gene pool concerns mentioned by that kentuckiense (there were only about 50 plants on my property of the pink and right around the same number of the yellow) as well as losses of specialized pollinators and I would absolutely cringe if I found out I had purchased a plant that was field collected regardless of whether it was from someone's own property or not. It's not in me to directly or indirectly promote field collection. Anyway, is this simply something that comes with time and getting a chance to allow a nursery's reputation to surface?

And what about ordering from a nursery such as this-
Supposedly, they flask on a special order basis. Not that I know what to do with an orchid that has been de-flasked but I did find one site that offered some direction that may or may not be within my skill set-
http://www.cypripedium.de/forum/Deflasking of Cypripedium seedlings.pdf

Previously I had asked for suggestions on books to purchase. I caught this suggestion in that other thread from the member named Rick, "Try getting John Tullock's book Growing Hardy Orchids. There are allot of soil (and comprehensive culture) recommendations for many species including acule in there." This sounds very good to me. Would anyone be able to recommend any others?
I'm not a cyp. grower so can only answer your one question of Matt Gore's site which is www.goreorchids.com/

He's a member here so you could also private message him or contact him through his site if he doesn't respond directly to your thread.
Thank you for the link. He doesn't currently have anything I would be interested in trying right now but inventories do change from time to time so I will peek back from time to time.

I found this online at a cp forum when googling for cultural requirements of C. acaule-

With five plants you can hope that one might survive. More than that would be unusual. If they all die then that might not reflect on you - it is just very hard to adapt wild-grown Cyp. acaule to cultivation, probably due to the quite profound fungal symbiosis that wild plants achieve. Plants propagated in vitro have lived their lives (outside of flask anyway) without such quite intimate contact with the fungus and can cope better with transplanting and so forth. But they are very expensive.

Soil can be either organic or mineral. I don't like the sound of the soil on the website linked to above. Peat and spagnum derivatives are not ideal in cultivation. There IS a semi-bog-growing form of C. acaule, but as yours come from woodland - along with all I have heard of in cultivation - don't attempt that as they will just rot away. Go for a humousy, acidic, pine-foresty mix with very good drainage:

Organic: mix equal parts pine needles, pine needle mulch, coarse sand and grit (sterilise the compost by baking in the oven and cooling prior to use)
Inorganic: mix equal parts seramis, grit and perlite

(Seramis might not be available in the US - I don't know. It's a medium-grade clay product. Perhaps lava/pumice granules would be a good subsitute)

Or create a hybrid of these soils - just has to be non-alkaline, moisture-retentive and very free draining. The problem with organic soils is that thay can harbour fungus and other undersirables, the benefit is that they add nutrition which the plants like. I use pine mulch from a local pine forest - in the US if you can get redwood mulch it will be even better as it's very acidic. My mix is seramis, grit, sand and this pine mulch.

The plants need very stronly acidic conditions at the root. The general method to achieve this is to dilute a teaspoon or two of cider vinegar with a liter of rainwater and water the plants with this. Other vinegars/organic acids don't give as good results for some reason.

Moderate shade. Soil moist in spring, allowing to dry somewhat more over summer until the plants die down (imitate the rainfall getting to the floor of a loose wodland as the trees start to shelter the floor really). I then put my pots out of doors for the winter to get the "normal" rainfall and frosts that they need for proper dormancy.

I have bought wild-collected plants (well, sourced on private property, but still for all intents and purposes, wild) and I know they come from a region where they are not under threat. However, the very high mortality rate for them means I doubt I will try this method again. It just isn't fair on the wild populations when we can't get them to transplant at all reliably. You won't know if you've been successful until the second year of new growth starts with them in your care.

Good luck!

Interesting that mention is made of a "semi-bog-growing form of C. acaule" as opposed to a woodland form of the plant. This person recommends pine needles in the medium. The pine needles actually sound as if they would be a fine addition. Presumably, any plant I purchase (not interested in purchasing field grown plants) will be the "semi-bog-growing form of C. acaule" mentioned by this person, am I correct?
Also, the search feature at the top of the page may be of use to you. If you click on the search button you can type in acaule or another type of cyp. that you're interested in and then the search parameters to find other threads about the subject. I know there have been several good threads on cyp. culture. Hope that helps.
Hi Candace, so far I have read 2/3rds of all threads in the Cypripedium Forum here. I did this before I made my first post. Somehow I missed the one started by that other new member JB Orchidguy but I found that last night and that's the thread from here by us where I pulled up the information I quoted above from Eric Muehlbauer on acaule. The other post that came up was fluke from when I googled and it happened to be a thread started by that same new member here on the same plant only at a different forum. I'm trying. I just am not too good with search engines. Not too good with computers in general but I try.
Oh, o.k. I didn't know if you had tried it. And I thought maybe you'd get some answers right away using it. Many people are at work and tied up so you'll probably get some answers soon. I'm not great with search engines either, you're not alone;>
Okay - Cyp. acaule is a very difficult plant to grow. It took me several tries to get it right. You should only attempt it if you have a few years' experience with hardy terrestrials - not necessarily Cyps, as it grows very differently from other Cyps. If you're going to grow it artificially (ie not introducing plants into an established natural growing site), I would recommend buying artificially propagated plants that have been nursery grown - they will be easier to establish. The plant needs a large hole to be dug and filled to the top 2" or so with pure acidic sand that cannot contain any lime whatsoever. Note that many sands you buy do contain lime so look out for that - perhaps collecting from coniferous woods is a better idea. You can soak the sand in a water/vinegar solution to further acidify it over night. You want a pH of 3-4.5. A pH of over 5 will quickly kill the plant. Then you'll spread the rhizome over the sand and cover with a combination of pine duff and partially composted pine needles, which you'll probably have to collect from a forest. Finally, mulch with some conifer needles to form a slight mound. I recommend planting in a raised bed or slight slope as it is sensitive to wet. A location with dappled shade is best. When growing, keep slightly moist the first season to establish the plant. Never fertilize and always use RO, distilled or rain water, mixed with vinegar (2 tbsps per 1 gallon water). After the first season, you don't need to water the plant, as it is quite drought-tolerant. Only water if it is a very abnormally dry year, and check the pH often, using the vinegar solution to adjust when necessary.
I found a lot of places I can get information online when I started googling but I don't have the time to join a gazillion forums so I picked this forum to join after reading a sampling of threads from other sites. This one seemed to have a diverse mix of mature members with few kiddies repeatedly getting totally off topic. I found the search engine here too and probably should have simply posted some of my questions right in that acaule thread started by that JB Orchidguy but I didn't want to get involved over there. I happen to believe I know a little bit about that situation and he "traded" those plants from a 16 or 17 year old kid who dug them up from his parents' property. Based on photos of the property that I have seen, my best guess is there were only about 25 orchids growing on the site. The other deal is that I caught in that post that this JB Orchidguy was asked how his 5 field collected acaule were doing and he didn't reply. I suspect they're dead which is a shame. No sense dredging up a thread like that by posting a new reply in it because evidently the member here named kentuckiense properly identified that new member who disappeared off the face of the earth for what he is. So, I think I'll stay here and get help here. I've got time on my hands to sort this out. Probably until next spring when the few plants I intend to order will be shipped. Lots of experience here even if most aren't in a position to respond immediately. Until just recently, I used to work full time myself. It certainly was difficult finding time to get online for myself with kids who needed the computers to get online for homework and such in the evenings.

You're a sweetie for giving me the heads up that most people are tied up at work though, I do appreciate that.
Oops, posting while parvi_17 was posting, really sorry about that.

Although I did order two C. arietinum, I have not ordered an acaule yet. Should I just stick to trying those two arietinum and maybe a kentuckiense and a reginae for now? You know, just because I want to try a plant doesn't mean I have to do it right now this instant. I'd rather wait if you think I'm going to destroy it.

Thanks for your comments. I could easily get my hands on as much pine duff and pine needles as I want because my property up north is predominantly coniferous forest. There are stands of white pine around here on people's property so I can also easily get white pine needles. Your growing instructions are very good, I don't know that I would be able to be constantly testing the pH more so because in the summer we are gone a lot and if there was a pH crash in a raised bed because of heavy rains (happens quite frequently around here), I take it that could kill acaule?
Well, if you have the materials, it's not like you HAVE to have experience (I was a little extreme in my last post), it's just handy. This plant is hard to grow in garden conditions, but in a specially created and maintained environment it is quite easy once established. If you want to try it, by all means give it a try; you'll have to try it sometime, right? The pH crash could be a serious problem, and for that reason you might need to create a microclimate for the acaules to avoid it. To do this, you would select a large area on your property, preferably populated by coniferous trees (though deciduous would do as well, or even large shrubs) and have all the soil in the upper level (top 12-16") amended with or replaced by the acidic sand, then covered in the pine duff/needles. This obviously is a lot of work, perhaps I'm being a little extreme by suggesting it, but it may be the only way if pH crashing is a problem. You could also build an alpine house (or even just a simple frame of modest size) or grow in pots. What I did is I just grew it in a raised bed in the same way explained above, but my climate is quite dry, so a pH crash isn't a problem.
I only have a deciduous woodland here where I live year round. It's up north where the coniferous forest and coniferous woodlands are. I did begin creating a windbreak of coniferous trees on this property. I used Pinus, strobus, P. banksiansa, and P. resinosa but they're all juveniles and not producing much duff or needles at all so collecting from this property is out. I do have a neighbor who has quite a few strobus on her property who likes her messy needles "cleaned up" and that's where I've been getting my needles to mulch some of my CP bogs.

I don't think you were extreme at all in your comments. I never even thought of a pH crash until you mentioned raised bed combined with an optimal pH of 3-4.5 with a pH greater than 5.0 being the kiss of death to acaule. Glad you mentioned that and good timing too because 4 days ago my rain gauges told me we received 4.5 inches of rain in under 3 hours, two days ago we received another 2-3", last night we received another 2-3" and low and behold I had a small pond crash. Nothing that a little baking soda couldn't fix but if I hadn't been home to deal with it, the critters in there would have been dead and I'm babysitting those fish for somebody else. That's way too much rain for small volumes of water or soil to handle particularly when one is in the habit of taking off for a few weeks at a time during the summer. Truly glad you mentioned the pH.

I'm not in a position to amend a large area of this property. Maybe someday when the trees in the windbreak begin taking off I will have that micro climate of which you speak. My guess would be about 10 years on that area.

What's an alpine house? Not that I'm up to one this year but I'd be interested in knowing what one is and how it applies to acaule.
An alpine house is essentially a greenhouse in which conditions of an alpine or subalpine area are maintained using special equipment. A lot of botanical gardens and serious hobbiests use these who operate in areas where such conditions do not occur naturally, or conditions occur in their area that do not in the natural habitat (such as heavy rainfall). Note that C. acaule probably does occur somewhere in your area, but in dense forest where it is protected from the heavy rains, which is why I suggested the microclimate. Alpine houses are expensive to build and maintain but are great if you are very serious in cultivating Cyps and other hardy terrestrials. You could also just build a simple coldframe or shadehouse, which would protect the plants from the rains and would be cheap to build, with no operating costs. If you are serious about Cyps, I would recommend that you buy Cribb's book, The Genus Cypripedium. It's a little outdated now what with the massive number of hybrids that have become available recently which are barely mentioned, but all of the cultural and taxonomic information within is completely valid. It explains in detail the cultivation of Cyps (including all of the rarer species) in each of the situations I've mentioned.
Thanks for the explanation. I can't afford something like that. I'm sort of embarrassed to say what we just spent on a new greenhouse what with permits, excavation costs, pouring the concrete and getting the drains in, connecting it to utilities, and then there was the little surprise of having to buy a swamp cooler. I still don't have all the proper shelving and other accessories in there yet because every time I turn around there is something else to buy so it's going to sit half empty for a while. If I ultimately go beyond being a native plant entry-level hobbiest with orhids, an Alpine house is going to have to wait until after the kids are out of college and that's a long ways off. For now, a simple cold frame might be in my budget. A simple cold frame has the added benefit of having no operating costs.

I'll have to re-think trying an acaule. You didn't discourage me from trying one, you just gave me good points to consider. Maybe I could work at looking for an appropriate location for a natural looking raised bed out in the woodland that might be able to accommodate one or two some day. Something that wouldn't stick out like a sore thumb.
I'm glad I was able to give you some useful input. There are, as I'm sure you already know, other Cyp species that are easy to establish in the garden. I've got C. pubescens, makasin, reginae and macranthos growing in my flower beds, along with several hybrids (which are fantastic plants). My selection of garden-worthy species is limited only to the sources I have nearby as I have yet to splurge on having some shipped in from elsewhere - there are other easier species too such as kentuckiense, calceolus (which isn't really easy but not hard either) and formosanum, and probably others too I've forgotten about. If you can get hybrids though, make an investment as they are wonderful!
Yes, you gave me a lot of good things to think about.

Backing up a little bit because I evidently got hung up on your comments about an Alpine house when dollar signs started getting stuck on my brain but you wrote this, "If you are serious about Cyps, I would recommend that you buy Cribb's book, The Genus Cypripedium. It's a little outdated now what with the massive number of hybrids that have become available recently which are barely mentioned, but all of the cultural and taxonomic information within is completely valid. It explains in detail the cultivation of Cyps (including all of the rarer species) in each of the situations I've mentioned."

Cribb's book will be perfectly fine as I'm not all that serious into any one orchid genus more so very serious about any plant that is native. It's the cultural and taxonomic information I'd be interested in. I'm definitely into straight species and naturally occurring hybrids than I am into the cultivars hitting the market.

There are, as I'm sure you already know, other Cyp species that are easy to establish in the garden. I've got C. pubescens, makasin, reginae and macranthos growing in my flower beds, along with several hybrids (which are fantastic plants). My selection of garden-worthy species is limited only to the sources I have nearby as I have yet to splurge on having some shipped in from elsewhere - there are other easier species too such as kentuckiense, calceolus (which isn't really easy but not hard either) and formosanum, and probably others too I've forgotten about. If you can get hybrids though, make an investment as they are wonderful!
I'm not all that familiar with Cyps other than I'd know one if I saw one and I am familiar with which ones are indigenous or not to my county. It's pretty bad when you own property and only know that one of the cyps growing on it is pink and might be acaule and one is yellow. Anyway, I garden down here not up there and use a book written by two men for whom I have the utmost respect, Floyd Swink (deceased) and Jerry Wilhelm. I've volunteered under both of them in the past. They wrote the book "Plants of the Chicago Region" and it's my Bible so to speak. They have documented populations of acaule, parviflorum, calceolus pubescens, candidum, and reginae throughout my county. Interestingly enough, of the species you mentioned above that are easy to establish, I do want to try the reginae and the kentuckiense you suggested. Someone else suggested parviflorum so I'll be checking into that one too. As far as the hybrids, tempting because of hybrid vigor and all but I'm thinking I'd rather try my hand at a 4-5 different species by getting those down pat so they will survive beyond the magical three years before branching out. Right now I'm narrowing down which 4 or 5 I will be trying to grow. The only one that I am for sure going to try is arietinum because I just ordered two of those.

Other hardy native terrestrial orchids that I will be exploring for this property will be Platanthera, Goodyera, and Aplectrum. Actually, any other orchids that I might be able to grow here that would be indigenous to Northern Illinois such as Galearis and Liparis will be checked into also. I do have Spiranthes here as well as Calopogon. Then there are my inside interests... so many plants, so little time.
so many plants, so little time.

I know exactly what you mean. Definately you should check out Cribb's book if you like Cyps; another good one is "Growing Hardy Orchids" by John Tullock, which has an entire section on C. acaule in fact, but covers many hardy genera with an emphasis on Cyps and Bletilla. With species Cyps, by far the easiest is Cyp. parviflorum var. pubescens. I have quite a few of these in my garden. Cyp. parviflorum var. parviflorum is very similar to var. makasin which I grow - they are both like pubescens but smaller. All three grow pretty much the same. The other ones you mentioned are great too, though arietinum I've heard is difficult (I think I already told you that); I have no experience with it but would try it if I had access to it. You also mentioned Cyp. candidum - one of my favorite species but hard to come by. If you ever get one, grow it with grasses as it likes more sun but not full sun; it naturalizes well with grass. A good substitute for it is C. x andrewsii, which I'm currently trying to get my hands on.
TheLorax, you asked about Troy Meyers Conservatory. I've purchased a bunch of plants from him, at several different times. I think I've gotten good value and excellent service from him. I'd certainly recommend him to anyone who is willing to grow species from seedlings or flask.
"Growing Hardy Orchids" by John Tullock was the other book recommended to me. I ordered it last night along with another publication titled, "Wild Orchids Across North America" by Keenan more so because I wanted to get a feel for the native plant communities in which they grew. I must admit my husband picked up two books for me for the few indoor orchids I have. One is "The Complete Guide to Orchids" endorsed by the American Orchid Society which looks ho hum for my purposes and the other is "Growing Orchids" by Ritterhausen and I haven't even opened that book up to take a peek. I can probably pick up the information I need for jewel orchids online so no big deal. I've got the Cribb's book on my list to order the next time I go to Amazon. Thanks much again for that suggestion. I should be good to go now for Cyp books between the two of those plus the one I selected.

Say parvi, I notice you live in Canada. Do you by any chance have a permit to import orchids that are an appendix II? That arietinum is a II and the man who owns the nursery over in the UK is a friend of mine who grows CPs who I met at Kew a long time ago. He's come over here and stayed with us with his whole family a few times and they're wonderful people. We're going back to stay with them next summer. You should see what the Brits can grow on a postage size lot! He doesn't have a lot of the arietinum but he had offered three to me for a very good price. I wanted only one because I was told here that they're difficult but he was pushing me to take all three to experiment growing them under different conditions. We settled on two for me which leaves one. I'm relatively confident he would sell it to you at the same price I'm paying which is £25 but he'd have costs that will probably be high shipping just one plant out to Cananda. I don't know what the exchange rate is off hand but it's usually not in our favor.

Cyp candidum I haven't checked into yet. I'm getting there between cleaning out cabinets and closets here, cooking, popping in here to see what's going on in my threads, and driving kids around. I'll go check out the C. x andrewsii per your suggestion.

I was given two Bletilla striata from a friend who said to keep them contained because they'd take off. So far so good on those. They bloomed an attractive medium purple but I dead headed them because they seemed to produce a decent quantity of seed. I think they're Asian but they were a gift.

Hi SlipperFan, I don't quite know if I'm ready for de-flasking just yet. I re-read that article on de-flasking and I dunno. I just backed out of trying to grow acaule so I'm not exactly a risk taker. Maybe if I have somebody to walk me through the process of growing cyps from seedlings next year. A topic for another thread some day in the dead of winter I suppose.
OK....a few things based on my experience. First- you mentioned a liner. I'd avoid that. Although I have heard about acaule growing in "bog" conditions, and once saw one blooming by a streamside, overall, I have found them to prefer very dry conditions. I have seen wild acaule's come back and bloom the year after they had 3 continuous months of no rain at all. Secondly, salvage plants are perfectly OK, ethically, although I'd agree that you can't trust just anybody. Check Carson Whitlow's CypHaven (on the Orchid Mall)..he usually puts out a new list at this time of year, and his salvaged plants are as kosher as can be. Several of my acaule's were salvaged plants from the Atlanta area. In my case, that was an advantage- they were pre-adapted to the heat of a LI summer...on the other hand, acaules from the north do not do well in our heat. Search you area thoroughly in late May, to see if acaule grows anywhere in your area. First, if the soil is the same, it will do OK with you. If not, then dig up as much soil as you can transport, and use that as your base. Rather than use a liner, sink a large pot into the ground (cheap nusery can type) and fill it with natural soil for acaule. I used to pollinate mine- sent some to Try Meyers, but they didn't work out. Haven't had enough blooms in recent years to pollinate again. Take care, Eric
That's what I get for walking away from the computer to try to eat... another good post came in.

Hi Eric- I pretty much got cold feet and talked myself out of trying acaule. I'll check with that Carson Whitlow of CypHaven and if I see any acaule show up available as salvage from anywhere around where I garden, I'll revisit trying to grow one. I have first-hand bad experiences with southern as opposed to northern races of the same species so I understand exactly what you mean by trying to locate a plant that would be from a location similar to mine. Location location location, just like what realtors try to drum into our heads.