Hippeastrum performance based on a consistent algorithm?

pizzuti(5A)September 16, 2011

Hippeastrum "behavior" and "maturity" seems to function not on a plant's age, but on a consistent core "math equation" of sorts, which is pretty simple. Each variety or genetically-distinct individual has its own slightly-different equation, yet under increasingly ideal growing circumstances, performance is increasingly consistent.

Your variable "inputs" are obviously water, light, nutrients, etc, but take it out of one environment and subsequent performance in a new environment shows all those previous factors have fused into a single variable: bulb size/stored energy.

So for these purposes, to determine when and how a hippeastrum will bloom, look at only two things: bulb size and environmental triggers.

Feel free to disagree with or "fact-check" anything below; it's based on a mix of reading, hearing from other growers and personal observations, but I think the bulk of this is accurate and pretty cool to know.

Not many plant species have the built-in clock systems that animal cells do, and a plant's "maturity" is based on size and environmental factors rather than age. For example, you can take a cutting from a mature tree and it will behave the same as a small tree grown from seed, and some clonal plant colonies live for tens of thousands of years.

You can plug in different variables to see how your hippeastrum will perform:

First, the seed sprouts, representing the smallest possible bulb. Obviously, it will not bloom as a seedling.

I heard via a botanist that hippeastrums produce one latent inflorescence per every 7 leaves, with some variance by variety; maybe 6 or 9, but in an individual plant it is very consistent. The embryonic flower spike will be kept latent within the bulb until the appropriate trigger causes it to develop.

So a hippeastrum will have it's first theoretical potential to bloom 7 leaves after sprouting (which will almost certainly be unsuccessful).

Small bulbs will often produce an inflorescence that aborts long before it would emerge. You may discover it a year or more later when the layers of bulb tissue have cycled through (one "leaf scale" is formed per leaf, produced on the inside of the bulb, progressing to the outside, where it eventually dries up and dies) and you find a dead undeveloped bud - or rather, the flat, dried husk of a flower stem empty of noticeable flowers - that can be anywhere between half an in inch and two inches tall.

Usually that's occuring under the soil but it is more noticeable in bulbs that are planted very high.

So I think that a hippeastrum that has produced 7 leaves is basically a miniature, yet (theoretically) mature plant.

A stressed bulb or one that is growing under unideal circumstances will likely be smaller, and will have inflorescences that abort in exactly the same way that a bulb that is too small does.

Meanwhile, a large bulb is accumulating latent inflorescences until they are triggered.

Blooming is usually triggered by increasing day length. That's occurring naturally just after December 21 in the Northern Hemisphere. But moving the plant from a windowsill where part of the daylight is blocked, to an outdoor patio, can trigger the same thing and you can get the plant to send up its latent blooms early, or more times per year resulting in more blooming periods with each producing fewer blooms.

Sometimes increasing the water can trigger blooming too.

Finally, a really enormous bulb sometimes randomly blooms for no apparent reason, but you only see one flower spike. I think it's just using up one of its latent buds before it cycles through and pops out on the outside of the bulb.

A personal observation of mine is that, by variety, there can be 3-7 flowers per inflorescence - but always the same number of blooms on each inflorescence on each plant (and clones).

You might be scratching your head, certain that they haven't been consistent for you. But that's because you will not always see all the flowers, because again, hippeastrums will produce blooming parts that don't develop. That includes individual flowers within one inflorescence. Based on the size of the bulb and its stored energy, 2, 3, 4, 5 etc of those potential flowers will actually mature and open, and the rest will be visible as very tiny pin-head-sized dried things hanging where the flowers come together on the main stem. On an inflorescence that doesn't have as many blooms as the others, look for them: they're small but there.

You may also sometimes see a flower bud that grew and died at a larger size within the inflorescence, and got to be maybe an inch long. I think that's caused by the bulb having less energy, now, than it did when it first "decided" to bloom and develop an inflorescence. The change in circumstances modifies the inputs of the equation mid-effort and therefore modifies the output of the number of blooms.

So one inflorescence may have 6 flowers and the next will have 4 flowers and two unnoticeably-tiny failed ones - but the "total" is 6. (Or a different number determined by the genetics of that plant.)

Now this is pretty common knowledge, but each hippeastrum leaf translates to one "leaf scale" on the bulb - which is a "layer" of bulb tissue, like what you see as layers on a sliced onion. That's true for all "true bulbs." The leaf scales form on the inside just as their respective leaves do, they migrate outward, expand and store more energy, and then die as an outermost layer.

Every time a plant blooms, you're likely to get 1-4 layers dying per bloom (just my observation), and also every time a plant puts out a couple more leaves you're likely to see an outer layer of the bulb die as it gives up its energy to create the leaves.

Sometimes leaves will abort the same way blooms do, and you will get a leaf scale that doesn't translate to a visible leaf. That's pretty rare but can happen if baby leaves were emerging just as the bulb was forced into dormancy, or if it tried to develop leaves while in dry storage. Or if something traumatic happened to it, like the pot tipped and smashed while new leaves were growing, and it decided to skip those and move on with the next inner set of leaves.

A bulb that is growing in size will do so because it is generating leaves/scales faster than the outer ones dry up. A bulb that is declining in size will lose leaf scales faster than they form. The leaf scales themselves don't "shrink," they only die back starting from the outermost one at a faster rate. Shrinking leaf scales would result in a squishy bulb, which you almost never see unless it is diseased; most likely even a bulb kept in dry storage way too long (like a year) will just lose a lot of layers and you'll have a firm, healthy but small inner bulb inside dozens of papery dry layers.

When hippeastrums finally bloom, you will always see that one inflorescence will emerge from between outer leaf scales, and the subsequent inflorescence will emerge from between inner leaf scales. If there is a third inflorescence in a single blooming period, it will emerge from close to the very center of the bulb, against the innermost leaves.

When only one large bud has just begun to emerge from the bulb, it's positioning will help you guess if more inflorescences are to follow. If the first flower bud emerges from between inner scales or from between still-living leaves, it means that all the older latent buds have either already bloomed, or already aborted. If it emerges from between outer scales, another is likely to follow soon.

A healthier bulb will maximize its potential to produce stems and blooms on each stem, which uses energy keeps its size in check. However, you can also see that there is a "maximum" amount of blooms a plant can produce since there can only be one inflorescence per seven leaves and around 6 blooms per inflorescence, and so you can push it and get bulbs that produce their peak level of flowering, at which point it will plateau, and then the bulb itself will continue to grow and can become obscenely large. They may actually bloom the exact same amount as a smaller bulb that is still healthy enough to max out.

But you don't see hippeastrum bulbs weighing 100 pounds. There is an additional way a bulb will keep itself in check and stop expanding based on self-limiting factors: a large bulb will produce offsets that draw from the parent.

I don't know if there's the same sort of routine pattern with which hippeastrums produce offsets that either abort in an embryonic stage, or grow, as is the case with flowers. A basal plate at the bottom of a bulb is analogous to a stem in other plants, so perhaps they could theoretically produce one "branch" (in the form of an offset) per leaf like any other plant can. I know if you hack a hippeastrum bulb to bits, you will get dozens of tiny bulbs on the basal plate. But that's just a guess.

But whether or not potential offsets are developed is triggered by a different set of circumstances from blooms.

Offsets usually start within the bulb, cycle outward and grow faster when they have surfaced, but I've seen a few seem to start on the outside.

The bulb will produce more offsets when root-bound, caused by a small container or crowding with other bulbs. It's counter-intuitive that bulbs would choose to multiply when they are short on space, but many growers have observed it.

I believe that being in dry storage and having no roots at all can also sometimes trigger the development of offsets which begin growing then, or after it is planted.

Evolutionarily, an offset is the same thing as expanding in size as far as a the organism is concerned - it's genetically identical. Even though it is a separate plant, it reflects an increased chance of genetic reproduction.

I've never experimented with the idea of plucking off baby offsets while they are small to see if you can grow a mega-bulb; I'd guess that the plant would compensate by trying to generate even more of them. But you could try it.

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Thank-you....thank-you... for such a complete, and very interesting description about bulb growing factors. I always wondered, and, now I know.

I asked some question about bulb maturity in another posting...before I read your explanations,... and all of those questions were explained here.

I personally enjoy reading all that you and others write about, mainly because it comes from practical experience and direct observation. I'm positive other readers benefit as well.

Thanks for taking all the time to set down your thoughts in these postings.


    Bookmark   September 16, 2011 at 6:32AM
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I benefited and loved this write up. Thanks for posting it!

    Bookmark   September 17, 2011 at 9:13PM
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anna_in_quebec(z4 QC)

Fascinating - I will copy and keep that.

    Bookmark   September 17, 2011 at 11:34PM
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very interesting...

    Bookmark   September 19, 2011 at 7:58AM
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I'm wondering if blooming is always caused by increased day length? Some Hippeastrum bloom in fall, winter and some are spring, summer? Do you know of any other triggers possibly?

Thanks ;)


    Bookmark   September 19, 2011 at 11:56AM
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I don't know about all hippeastrums. Any that I've grown have bloomed in spring.

However, in some situations indoors, day length (as the plant perceives it) can be complicated by many factors. For example, as the sun moves South in fall, it can begin to break out from under a patio roof so the hippeastrums suddenly get direct light when they weren't during the summer. Deciduous trees outside lose their leaves and also allow for direct sunlight to find them in a window.

Especially consider that in a window that faces directly East or directly West, the summer sun comes straight down from the top of the window to the bottom of the window and buries itself in the ground. That's a couple hours of direct light for your hippeastrum. The winter sun will come in at an angle and take longer to set. Direct sunlight could be striking the leaves 50 percent longer. So the plant might perceive a longer day. Additionally, the last hour of daylight that may have been blocked by the neighbor's tree during summer will shine right on the plant since the tree is bare for winter.

But if your hippeastrum blooms in fall very consistently and seems to do so no matter where it's located - and if other growers in slightly different settings report the same thing, then decreasing day length must cause it instead in that individual or variety. I would just keep an eye on the possibility that even though you know the days are getting shorter, they might be seeming longer for your plant.

I think some varieties are more sensitive than others... I have grown a "wild" species form that has been in our family for over 80 years. That one is triggered so easily that sometimes just turning the plant around, or leaving it on the counter for a few days, then putting it back on the windowsill, can cause it to bloom if it's ready.

    Bookmark   September 19, 2011 at 12:53PM
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Thanks for the information ;)

Some species like H. aulicum, H. calyptratum and sometimes H. papilio bloom in the fall but I think all could bloom as well after a winter dormancy but they also are dormant during summer in their wild locations but most are evergreen and just quit growing during summer.

I wonder if there are other triggers because even evergreen hybrids bloom in early spring?


    Bookmark   September 19, 2011 at 6:26PM
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Yes ;), y-e-s :)), it is "interesting" - but what with the summer flowering, flowering or at any other time of year?
So I bought new bulbs in early September, planted in a pot - and has already struck the top of the scapes. While I'm waiting to bloom in February.And it's not cybister, papilio, aulicum, or other exotic species, but the usual Dutch hybrids.
(To himself) And why would SO many UNFOUNDED theoretical reasoning? And what is the PROOF? And why is it TAKEN? And WHY?

    Bookmark   September 19, 2011 at 11:12PM
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They can flower in the summer because summer is also a period of increasing daylight. If you move it from a porch to outside, increased daylight.

A newly planted bulb goes from zero capacity to recognize whatever daylight is there, to daylight. So it can also bloom.

But as I said water can be a trigger as well...

    Bookmark   September 20, 2011 at 1:45AM
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This is called the "iron logic": If the facts contradict the "theory" - the worse for the facts.

Here is what a scientist from the Netherlands Joop Doorduin (1990) Glasshouse Crops Research Station in the article "Leaf and flover initiation":[citate]Initiation and development of flower buds and leaves, does not depend on the intensity of the light of day it is due to internal resources bulbs ... initiation of flower buds occurs every 11,5-13 weeks [/citate]
These studies used the Veronica Reed in his book.

So what? Next we will discover wheel?

    Bookmark   September 20, 2011 at 5:40AM
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As I said you can feel free to fact check this because it's a mix of advice from different sources. Sorry if the question mark in the title was not enough to indicate that what I offered is a starting-point. But I was hoping that others might provide information that replaces some parts of a working theory, to the benefit of everyone.

I find that an incomplete "theory" is often more useful than accurate "advice." That's because a person's good record of his/her personal gardening techniques may be totally unrelated to your particular location, circumstances, disposition, and abilities, plus when they advise something that works for them they may not realize you lack other information that would tell you how to do what they advise.

But if you instead use your knowledge to get inside the plant and understand how it works, from there you can creatively improvise to get it what it needs in many different ways.

In education this is called "conceptual knowledge" vs "procedural knowledge" and it is the former category that is considered to be far more useful to a maturing student; they will someday have questions that do not relate to what was specifically taught in school as "facts," or if they forget "facts" and have to figure out how to remember them. In the same way I think explaining "what's going on" in the plant is going to take you much farther than "you should water it like this and plant it like this." You can invent your own techniques when you understand "what's going on."

What I thought was most interesting - that hippeastrums produce an embryonic bud every 7 leaves and it can either abort or grow - came from a professional botanist here in Denver. I think that is really useful in telling growers how many blooms to expect or how often it can bloom or why a really healthy plant doesn't just bloom constantly.

Maybe the quote you are citing refers to just that - that the bulb produces embryonic buds on a regular schedule regardless of whether they are triggered to bloom. Not sure what was meant by "initiate." But surely they bloom far less often than every 5-13 weeks. Right?

I am assuming that many of us on this forum are not trained botanists, and even whatever science is done on hippeastrums is tilted towards techniques for commercial growing which don't apply to hobbyists. So we are just going to have to do our own science and put together our observations to make theories that apply to our own settings, and I think we can do that successfully as a group.

This gardening forum may not look much like a peer-reviewed journal...but remember that genetics were discovered by a gardener with no scientific background!

Now when observations come in that contradict your theory, your first response is going to see if some nuance or quirk allows them to fit into your theory anyway. That's why I suggest that some hippeastrums that appear to bloom in fall could be seeing increased light because the sun is getting lower in the sky, so still fit the same picture. Or maybe there are specific varieties that bloom in fall but the ones I have worked with are still spring-blooming types.

If light is not a factor in hippeastrum blooming, I would then turn to you and ask how it is that they all "know" to bloom in spring when they're in my windowsill even though they were on all different clocks originally, that it doesn't seem to relate to water...and how is it that they will bloom a second time during the same year if they are put outside on a porch where the light increases further, again, unrelated to watering, and definitely "off the clock" they would internally have?

Very happy to replace my ideas with new ones - but I find that knowledge increases at a faster rate when you have a theory to begin with, even if it ends up being wrong.

So dive in and tell me what you know that improves any of this.

    Bookmark   September 20, 2011 at 2:54PM
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Too many words, questions, and so on.
My answer is this: I find it hard to understand all the nuances of your message is not too short especially since English is not my native language.
Information about what a flower bud hippeastrum initiated through the leaves every 7 - is not accurate. In conventional Holland hybrids grown your is initiated every 4 large mature leaves.
I would like you to understand research - it's not "argument on the subject ..."
they require a lot of special knowledge, equipment, materials, time consuming and expensive. So naturally I'm not able to fulfill your desires.
Especially for you - it is not necessary, simply - see the next topic:What exactly triggers scapes in amaryllis bulbs to emerge?
And another tip: before you write kilometer messages, read the first literature, the topic at the forums, search the Internet. Because I have for you is simply inconvenient.

    Bookmark   September 20, 2011 at 5:06PM
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I will be growing some Hipps. again for the first time in over 25 years. The information that all you forum members post is very useful and, is really, "food for thought"....a starting point. I especially like the growing suggestions that are based on direct observation(s),-usually by hobbyist growers- and not based on gigantic commercial growers.

Thanks for taking time to post, and pass-on information based on your experiences.


    Bookmark   September 20, 2011 at 6:29PM
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Thanks for your comments, I understand your position about the length of the post and it was mostly to get all the information in one spot (understanding it is redundant in places for other posts) for those who are willing to stick through it. It is easier for some people. Obviously not everyone will think it's the best way to present the information but I don't think the presence of the post being here is a problem since they can still get the information in smaller chunks from other posts.

I read through that other thread you mentioned and it seems the observation is about the same ... increasing day length triggers blooms to emerge. The comments speculate that a certain day length may trigger them but note that it doesn't happen in August, only March. That is when day length is increasing in the Northern Hemisphere.

There also seem to be comments that they do not bloom at all when grown outdoors in certain areas, which seem to be coming from low-latitudes close to the equator where day length does not vary much. There, the variance in day length may be insufficient to cause them to bloom, which also seems to support what I was suggesting.

I added the theory that anything that removes the leaves can trigger blooms because while they are not receiving any leaves, it is like there is no light at all to produce whatever hormone inside the plant is created during long days. So when they return to having them, they "think" the light levels are sharply increasing. I don't know if that's true or not, hopefully others can offer insights.

Pertaining to your comment about embryonic buds being produced each 4 leaves instead of 7: the quote I heard from my source was 7, and specifically stated a seedling could theoretically produce a bloom after 7 leaves if it had the energy, which almost none do at that point. However, I did also mention that it varies by individual. It's interesting to think they could bloom as often as every 4 leaves!

    Bookmark   September 20, 2011 at 8:51PM
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