Lilies forum: Cutting stems prematurely to induce early dormancy

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Name: Rick R.
near Minneapolis, MN, USA zon
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Hybridizer
Seed Starter Plant Identifier Million Pollinator Garden Challenge
Sep 20, 2013 12:18 PM CST
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Oh my gosh, the length of this post is staggering! Those of you who are familiar (or unfamiliar) with my boring technical talk might wish to pass on this. I certainly won’t be offended. Big Grin
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The premise:
Cutting green lily stems before they naturally senesce will encourage earlier dormancy of a lily bulb.

Does this work? In all probability, yes. No argument there.
I am just not sure if a simple, immediate transplanting warrants the action, even if that means transplanting with a green stem and in a not so dormant state.

In a case where we would want growth to cease and the metabolic rate decline to its lowest rate earlier than normal for the climate, I perceive this stem cutting technique as useful. As you say Lorn, storage and shipping are eligible situations, where the length of time in this dormant state is undefined. But for a simple transplanting, may I encourage some thoughts outside the box for a moment.

We, as gardeners, tend to have a general rule ingrained in our psyche: the best time to transplant is when it is dormant, whatever time of the year that may be. This paradigm “applies” to all plants, not just lilies, and I compare it to thinking inside the box. I suppose, as a best guess, this is a good standby answer. But my concession here doesn't mean it's always the right or best answer. As an example, it is known that trilliums are best transplanted right after blooming. In fact, Eugene Fox in his book Martagon Lilies states that transplanting martagons is most successful soon after flowering, too.

To the case in point:
For fall transplanting of orientpets (OTs) whose stems senesce too late in the fall or even stay green into early winter, is it beneficial to induce an earlier dormancy that would then seem to coincide with the "best time to transplant"?

Let’s consider our objectives:
1. --- to cause as little stress as possible on the plant.
2. --- to encourage fast, sustained establishment in its new environment.

If we were only to consider #1 as our goal, then definitely, transplanting a lily bulb in its most dormant state would be the optimum choice. The bulb is least vulnerable to outside influences at this time. But I submit that the more important objective is #2 (long term establishment). Is this also accomplished with a bulb in its dormant state? This is what I want to explore.

For the majority of lily types, minimal stress and most successful establishment usually go hand in hand because the natural growth phenology (timing) is synchronized to allow it. That is, both objectives can be accomplished at the same point in time. But for some lilies like OTs, the natural timing of dormancy in our northern climes may put us into winter. Obviously, that’s not the time to be transplanting! So what is one to do? As I see it, we have two basic options:

#1 - Attempt to artificially synchronize growth phenology to encourage dormancy at a more “amenable” time as Lorn suggests, by prematurely cutting down the green stems, or by other means, like withholding water.

#2 - Work with the natural growth pattern of the plant: a “go with the flow” approach.

If it were only that easy…..

OTs are not a natural species, but man made. Futzing with mother nature doesn’t always have perfect results, hence our quandary here. To jump ahead a bit, I’ll let you know that my solution is a hybrid of the options. In a mathematical sense, it seems quite fitting. nodding

Option #2 is scientifically uncharted territory. Although most of us do it, we really don’t know what the ramifications are, or even if those ramifications are relevant. We just guess, trying to find the happy medium between dormancy and length of time for reestablishment. Fortunately, plants are very resilient and forgiving.

Option #1 we know (or think we know) what the intended outcome is: induced early dormancy. Is this necessarily a good thing? What about other side effects? Here is where my thinking diverges from the norm.

Most of us have experienced the difference in subsequent top growth of a bulb planted in the fall versus a bulb planted in the spring. Stems of spring planted bulbs are usually dwarfed in comparison, with flower buds that often abort. This is because a spring planted bulb doesn't have the time to establish itself as well as a fall planted bulb, in preparation for the ensuing rapid spring growth. We know that OTs require a longer time to establish themselves in a new environment than trumpets or asiatics, for instance. So I think it’s important that we keep this characteristic in mind. I think we need to at least preserve the length of time for reestablishment of transplanted OTs, rather than shorten it through early dormancy induction.

---- Theoretically, to achieve a kind of OT bulb dormancy for transplanting, one would need to cut stems weeks in advance to allow for the changeover. But cutting leaves conceivably 2 months before natural senescence would have an impact on potential bulb size, reducing its would be bulk. I don’t see this as a detriment to the lily’s overall health, just its vigor.

---- More important is the actual apparent switch over to a dormancy mode. Is this congruent with objective #2 - sustained reestablishment? It’s a matter of degree, a lily will reestablish no matter what, eventually. But no, I don’t think this is optimal. We must remember that Lilies do not go completely dormant like a tulip. The metabolism slows, but never goes into stasis.
In its uncut (still with green stem), natural state, an OT lily still wants to keep growing underground, still wants to make more roots for good establishment for the ensuing growing season. A plant with foliage has the ability to continue to manufacture additional food and energy for such growth, rather than to draw on its bulb reserves. Does this underground growth still happen after an induced dormancy (by cutting green stems)? Yes, but certainly to a lesser degree than a plant that still has its leaves, or one that is not in the dormant state.

But transplanting with the green stem certainly causes much stress that, in my opinion, cannot be compensated for in the fall, as the transplanted plant will, at least initially, attempt to supply the above ground anatomy with needed nutrients. So this is not optimal either.

My hybrid solution is to retain the green stems up to the time of transplanting, and then cut them. The plant would still be in an active state, but without topgrowth to support, until the effects of cutting the stems induce dormancy. This, in my view, would provide maximum food storage and maximum underground growth potential for reestablishment.
Name: Lorn (Roosterlorn)
S.E Wisconsin (Zone 5b)
Lilies Seed Starter Pollen collector Bee Lover Region: Wisconsin
Sep 21, 2013 6:57 AM CST
Well, it turns out that I've been using your hybrid solution successfully here in Z5A/B. That is, growing them to the last possible moment to get as much as I can into them. And for me at my location, it means cutting, digging and planting the second half of Oct. because I want be sure I provide the replanted bulbs with a good month to six weeks of settle in time before the soil temps go too low. But my curious mind always drives me to wander if there is a better way. And sometimes, short of getting laughed at, one should think outside the box. Like you say, Rick, our whole gardening life style is so engrained around working with the 'natural' cycle of plants that we automatically use our routine techniques with the not so natural (man made) cultivars that push the natural to an extreme in one direction or another.

I know from experience that Division VI bulbs, once dormant and slightly thirsty, re-root rapidly. On more occasions than I care to admit--ha-ha-- I've decided to re-dig and re-plant in yet another location. In just five or six days a good dozen or more tiny little bulb sustaining feeder roots and inch, 2.5cm or so long are emanating from the basil. This may be true for all dormant, slightly thirsty lily bulbs. They settle in very well in preparation for next years growth pattern--albeit a little less, usually. With primary focus on bulb adjustment only and if I accept the above to be true; then, if concern myself with somewhat tunnel vision to only that narrow timeframe of how well dormant, thirsty bulbs respond, then why not force dormancy (not a question). Again concerning myself primarily on the bulbs adjustment by giving my bulbs a good four to six weeks settle in time before wintery climate sets in. That was my thinking.

But, as you said, it isn't that simple--I agree. There are trade-offs as you very well presented. One can't focus on a single aspect alone without at least some consideration of all the others. I read you discussion twice and some parts a third, developing many sub thoughts along the way. If I had more OTs to play with around here, I might try forcing premature dormancy, but until then, I'll stick with your 'hybrid solution'.

Name: Rick R.
near Minneapolis, MN, USA zon
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Hybridizer
Seed Starter Plant Identifier Million Pollinator Garden Challenge
Sep 21, 2013 9:03 PM CST
Thanks for your insight, Lorn. I really don't see a lot of set back happening if you re-dig a fairly recently planted (1-3 weeks) bulb in the fall. As long as the root breakage is minimal, a re-planting would not be very stressful at all. When you think that the roots don't support anything that is dependent on them until spring growth, what is there to cause stress? Root hairs are always decimated, but they grow back amazingly quickly, and in fact are in a constant death and regrow cycle, anyway.

I'm also not surprised that for some kinds of lilies, such specific considerations as I outlined are really inconsequential. It's the ones known to be fussy, or slower to establish, that need extra care.

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