PBS Forum

Hi Anita,

I don't stratify, and sow as quickly after harvest as I can. I've never tested to see if they'd germinate after dry storage but I suspect it would be much reduced if at all. I usually put the pots near the edge of the greenhouse, which is frost-free but can get down to the low 30s F (near 0 C) briefly on the coldest nights.

But here in NW Arkansas, US, USDA zone 6 or 7, the ones I don't collect and just let fall where they will outside germinate and do fine on their own, even in areas that are not mulched other than whatever tree leaves fall. While digging Lycoris to give others, I've encountered these seedlings, and the radicles can go 6 in (15 cm) into the soil with no leaves showing until the next growing cycle, so don't give up if you don't see action above the soil right away.

There's always an exception so maybe x squamigera does make a viable seed now and then, but in about 35 years I've never had one make any seed at all. They always appear to be setting pods, which always yellow and abort with no actual seeds inside.

There are other Lycoris growers a lot more knowledgeable than me here, I hope they'll chime in.

Steve

Quote from: CG100 on September 09, 2024, 10:01:37 AMEvery day is a school-day.

Never heard of Amorphophallus being propagated via leaf cuttings before.

Assuming that all Amorphophallus are actually Amorphophallus, is this possible with all species?

It's a big genus spread from Africa to Australia and a wide range of habitats, and probably many have never been tried. But it seems most can, though the success rate varies widely from species to species. Oddly, to me anyway, A. konjac, which is the hardiest (it's survived -20 F [-29 C] in the ground here several times), probably the most commonly grown, and which offsets prolifically, is rather difficult to propagate from leaf cuttings. Others, like A. parvulus (now harmandii) are almost 100% if the cutting is taken at the right time. I've not tried any of the really tiny ones like myosuroides or ongsakulii.

My experience is that rooting leaf cuttings of the tuberous aroid genera in general varies widely. I think every leaflet of Gonatopus boivinii that falls off and lands on soil will root and form a tuber with no help. I used to find them all over the place in the sun room. But I've tried leaf cuttings of Taccarum weddellianum, several times with no success. I've also failed with the very few Arisaema leaves I've been willing to sacrifice to experimentation, but I think Tony has had some success in that genus.

Steve

Hi Aad,

I've been propagating Amorphophallus this way for more than 30 years now, but just casually, to make plants to give friends. The PDN link you posted is by far the best write-up I've seen, and has data on the most species. They're the experts.

A couple of comments. PDN removed 2/3 of the leaf, leaving 1/3 to provide energy to the existing plant. I've never been that brave, and always stop at 1/3. For larger species, that 1/3 can be divided into 2-3 cuttings (or more), as they did, but for smaller ones I just leave it a single cutting. I have no scientific data to support this statement, but it seems reasonable that there is a minimum leaf area needed to collect enough energy to produce a viable tuber before the natural senescence of the leaf occurs.

Timing of the leaf cutting seems important. PDN suggests waiting about 4 weeks after leaf emergence to take cuttings, and I'd agree. But at some point, as the leaf ages, the likelihood of success from cuttings of it goes down dramatically, and my experience is if there's the slightest bit of yellow, indicating the leaf is beginning to senesce, there's no chance at all. This still leaves you usually some weeks of viability, but don't want too long.

Without a commercial propagation setup like Tony's, after application of rooting hormone I stick them in damp perlite and put in a plastic bag (ziploc) with the top folded over but not sealed, and in bright light but not direct sun. Then wait. Don't let the medium dry out. Eventually the leaf turns yellow, collapses, and disintegrates, just as it would on the plant, and that's when I dig into the perlite to see if there's a tuber or not.

Good luck!

Steve

Quote from: CG100 on September 05, 2024, 10:06:56 AMPresumably seed is not ephemeral, even if not long-lived?

Germination - gentle warmth, bottom heat?

My experience is only with those 2 species (hasseltii & gardnerianum) but for them, yes, except that I didn't find bottom heat necessary - both germinated well enough at room temperature and in a reasonable time, i.e. weeks not months.

I collected seed from my hasseltii several times over the years I had it, so more experience with it. It's been a while, but I believe I sowed it as much as 5 or 6 months after collection, stored at room temperature, and didn't notice any difference in germination. But years later, after I lost the plant my friend sent me and had given away all the offspring, I found some old seed I'd saved and didn't get any germination.

Steve

I've grown only two, H. hasseltii and H. gardnerianum. H. hasseltii is a smaller species and I kept in in the sun room, as I'm sure it's not hardy here (NW Arkansas US, formerly USDA 6b, now 7a, FWIW). I've since lost it, which I hate because it's a great plant, attractive all the time and the fragrance of the flowers, especially at night, was wonderful. I'd love to have it again now that I have better conditions. It was not a rampant grower.

H. gardnerianum I grew from seeds donated by Alberto Grossi to BX 143 in 2007. By then we had a greenhouse and I put it in a 3 quart pot on the floor at the base of a bench. It's a much larger and more vigorous species and I can easily believe that it could be invasive in the right climate. It split that pot long ago, settled on the dirt floor, and has been going strong since with no assistance from me. It flowers every year - I think another spike will be open soon - and goes dormant every fall, though late growths like this one may hang around into October or November before dying back and dehiscing neatly at the top of the rhizome. The greenhouse is always above freezing, but temps on the floor reach the 40-50 F (5-10 C) range, maybe a little lower, on cold winter nights. I believe this one is considered hardy to USDA z7, and there is so much of it I'm going to try a piece outdoors this winter, well mulched. To me fragrance is a little strong close up but quite nice when I walk into the greenhouse when it's blooming, and the inflorescences are impressive.

Steve

My experience matches CG100. I get germination if sown within several months of harvest, but the sooner sown the better the percentage. I've never had year-old Drimia/Drimiopsis/Ledebouria germinate.

I sow them in a well-drained mix. When they germinate, I let them guide me. If they seem to want to go dormant, I back off the water and let them. If they stay green, I keep watering them.

Steve

As far as I can tell, if you have the basic information - temperature, air pressure, and partial pressure of water vapor - then RH, dewpoint, and VPD are different ways of looking at the same thing. There are formulas and tables that let you get to any of them or convert between them. I grew up with RH. The weather people now, at least in the US, like dewpoint, for technical reasons, and the crop science people like VPD, also for technical reasons.

I also use Bluetooth enabled sensors (SensorPush), and it lets me display any or all of those three values. I tend to look at RH first since I'm most familiar with it, but I've got the VPD display turned on and am trying to get used to looking at it for the greenhouse sensor.

I agree strongly with Peter that leaf temperature is in many, maybe even most, cases, more important in knowing whether the plant is too hot than is air temperature, especially with C3 plants. High levels of photorespiration can become detrimental very quickly. (What I can practically do about that in my growing situation, other than more shade, is unfortunately a whole other question.)

The only real use I make of any of those numbers is deciding whether to spray water on the GH floor to increase RH/reduce VPD for the cuttings and seedlings, since they're so sensitive to water stress.

Thanks for the link to "Plant Empowerment", Peter. Looks like some good information there.

I can't help with the question, as I've never gotten seeds from either of the two Velloziaceae I have - this one, Xerophyta retinervis, and X. (formerly Talbotia) elegans. 

I don't want to hijack the thread, but if you have advice on pollination, I'd love to hear it. X. elegans in particular flowers freely every spring, but has resisted all my attempts to self it. I don't know if this is due to self-incompatibility or if there's a trick, and haven't found much information.

A friend who spent time in Brasil with Burle-Marx and saw a lot of Vellozia in habitat, and grew some, thinks it should be straightforward, but Xerophyta are from the African branch of the family so ??

I'd also appreciate a pointer if anyone knows of sources for other Velloziaceae.

Steve

Depends very much on the size/shape of the flowers and the particular species, since some things have special requirements. But for general pollination I use cotton swabs a lot, sometimes clipping or shaping the cotton a little, sometimes dry, sometimes damp. Very cheap, available in quantity, disposable (the ones with paper spindles are compostable), and seem to work pretty well. If I'm doing controlled pollinations among specific plants I can mark the spindles with a felt-tip pen to help track whose pollen is where.

I haven't tried Lachenalia, but have had good results with them on various Ledebourias.

Steve

Quote from: David Pilling on September 24, 2023, 10:01:36 AMspider repellent... things like ticks and chiggers are spiders, and things like deet are repellents for them.

Or if not repel them, at least leave them confused:

https://www.sciencedaily.com/releases/2018/09/180926140832.htm

Steve

Lee, this is very interesting. I've been fascinated by color since I heard a talk by an ornithologist who was studying the visual system of birds (this was back before I paid much attention to birds, so I don't recall now why I was even there). He showed examples of colors that looked identical to most humans, but were composed of different frequencies of light and look very different to birds. Many birds are tetrachromats, with different color sensitivities than ours, including into the ultraviolet.

I started casually following the efforts of plant breeders, and in some cases gene shufflers, to achieve colors not found in nature, such as the blue rose or blue Phalaenopsis orchid (which was modified to produce the blue pigment in Delphiniums). But I hadn't considered the question you asked, which is a great one. And I like your answer! I've seen pictures of 'Masquerade'. If only I could keep Anigozanthos alive.

David, re your question of other ways to produce color than pigments, some plants also produce "structural color", derived from the way light interacts with nanoscale structures. (As do some birds and insects; I've read that all blue color in bird feathers is from structure rather than pigment.) I've been slowly accumulating research papers on this topic for years, and still don't have very many.

You also reminded me that I saved a couple of papers on how to use a cheap plastic diffraction grating and the standard camera in a smartphone, with some software from the Android app store, to make a spectrometer. I need to dig those out and actually try it. One more project for my overflowing list.

Steve

Jim,

I'm no expert on California native plants, but as a milkweed enthusiast I'll suggest a nearly spent Asclepias californica.

Steve

Plants of the World (Kew) says they are native to Burundi, Chad, Ethiopia, Malawi, Mozambique, and Tanzania, and that "It is a tuberous geophyte and grows primarily in the seasonally dry tropical biome".

I grew them (NW Arkansas, US) long ago. They came back and flowered for several years, more reliably than the hybrid gladiolus sold everywhere do here, until an unusually cold winter - a fairly common story for me. Of course that was back when winters were significantly colder, so maybe I should try again.

Steve

I believe this just means that while the names are considered synonyms, the heterotypic synonym is based on a different specimen ("type") than the one on which the currently accepted name is based. A homotypic synonym is a name that is not the currently accepted name, but was based on the same specimen. You can see the definitions here: https://www.iapt-taxon.org/nomen/pages/main/glossary.html

A botanist publishes a new species, Species A based on specimen A. Another botanist decides later that it has to be renamed for some reason so it's now Species B, but since that name is still based on specimen A, the original name (Species A) becomes a homotypic synonym. Meanwhile, someone decides Species C, whose name was based on specimen C, is really the same species, but is a junior (later) name, so Species C becomes a heterotypic synonym.

I welcome correction from those more knowledgeable about botanical nomenclature.

As to what name you should use, I can only tell you what I do. In general, I use the currently accepted name (i.e., the newest one, even if that happens to be an old name that's been revived). If I happen to know that species or genus is the subject of ongoing work and is still in question, or if I know that very few people have switched over to the currently accepted name yet, I'll put a couple of names on the tag. If I think for some reason the name given by the collector is wrong, I'll use what I think it is and note "received as" on the tag. (Yeah, my tags get pretty cluttered. Sometimes there's more than one.)

Steve

Thanks for that information, Martin. I'm interested in this topic too, so I hope others will contribute their experiences. Of your list, I've only intentionally grown oca, Oxalis tuberosa. I ordered several cultivars in the spring. I had tremendous foliage growth from all of them all summer long, but in the fall, zero tubers. I knew they were a long shot with the summer heat here (NW Arkansas, US) and this year the heat lasted even longer than usual, so I was prepared for the failure. I've looked for heat tolerant cultivars but never found one.

Unintentionally, Cyperus esculentus is considered both native and introduced across most of the US, including here, and I think I killed off a stand of it in the yard when we moved here. Maybe I should try growing it intentionally. (But potted.)

Steve

Steve