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Synchrony vs. Continuity

Posted: Tue Dec 06, 2016 3:48 pm
by Karl K
Flower Breeding and Genetics: Issues, Challenges and Opportunities for the 21st Century (2007) pp. 722‑723
By Neil O. Anderson

6.10 Recurrent Bloom

Non‑vernalization requiring roses that flower continually over the entire growing season are preferred by most rose growers. The market for roses that bloom prolifically for a short season in spring (once blooming), only after flower initiation is triggered by vernalization, has become increasingly small. Fortunately, the inheritance of recurrent bloom is relatively straightforward and is controlled by a major locus with recurrent bloom expressed in homozygous recessive genotypes (de Vries and Dubois, 1978 and 1984; Semeniuk, 1971a, 1971b). Complementation reveals that the same major gene governs recurrent bloom in hybrid china / hybrid rugosa crosses and crosses between the hybrid china descendant 'Goldilocks' and a recurrent flowering variant of R. wichuraiana (Semeniuk, 1971a, 1971b; Svejda, 1974). In addition, minor genes appear to be involved that regulate the expression of recurrent bloom. Some recurrent blooming roses tend to produce distinct cycles of bloom with relative synchrony (e.g. 'Therese Bugnet'), while others tend to be more free‑flowering with plants having at least some blooms open at most times during the growing season (e.g. 'Nearly Wild'). A more free‑flowering, recurrent habit is favored by most gardeners and commercial growers. ... &q&f=false
I first noticed this difference in flowering behavior between 'Mutabilis' and 'Mateo's Silk Butterflies' (Mutabilis seedling). 'Mutabilis' is as continuous flowering as any rose I've seen. In favored locations in California it flowered year-round, though there were fewer blooms in the winter. 'Mateo's Silk Butterflies', on the other hand, tends to bloom in distinct flushes. I don't care much for the pale, lavender-toned flowers, but there is something to be said for recurrent masses of bloom.

Last year my 'Paul's Scarlet Climber' bloomed nicely in the Spring, then put out only a bloom or three over the rest of the season. This year, however, it gave at least five flushes of bloom. The first one was the best, but the repeat flushes were much more impressive than a similar number of blooms scattered over the summer.

I think this synchronous flushing would be a particularly desirable trait for climbers, and for shrubs used in landscape plantings.

I'm anxious to know of other varieties that tend to "flush".


Re: Synchrony vs. Continuity

Posted: Tue Dec 06, 2016 11:15 pm
by Larry Davis
For us the flushes are often connected to stress and its release. For some plants it seems like they bloom well again only in the later cooler times, even though all are watered as needed in pots. Setting seeds may make flowering quit until hips are removed or ripe. ON campus, hard pruning is used on things like Sunrise/sunset to induce a distinct new cycle of bloom in synchrony, even though the seed set is so small that it ought to have a negligible effect of resource allocation. The KO series also respond remarkably well to a hard pruning and I think end up with a net increase of total blooms over the season. But I haven't actually counted totals. I've seen really different effects on Therese Bugnet as a function of soil type, on its own roots. Some summers on deep rich soil it will bloom continually. AT my house not so much. Pruning right after first flush will stimulate primocane blooming. Then with moisture there is another round.

So, are we talking unpruned, dead-headed, hard pruned? Each is different.

Re: Synchrony vs. Continuity

Posted: Wed Dec 07, 2016 8:50 am
by Karl K

"Induced vs inherent" is a good point of discussion.

I have a note by "An Expert" (1885) regarding his technique for forcing 'Rose Edouard' to bloom in flushes rather than continuously. The blooms were better and more uniform. ... d1885.html

But what I have in mind is an inherent tendency to bloom synchronously. A large shrub that blooms in 3 or 4 or 5 major flushes without pampering would be (I think) more impressive than a similar shrub that scatters its blooms continuously. Likewise, a climber that puts on a show like a once-blooming rambler, repeated 3 or 4 times each year, would be more dramatic than one that always has a handful of blooms.


Re: Synchrony vs. Continuity

Posted: Sat Dec 31, 2016 11:16 pm
by jriekstins
It seems that "induced vs. inherent" might be the real question here. Who has not whacked back, given a little super nutrients and then watered well in anticipation of a special event,i.e., guests, wedding, reunion, etc., and turned a continuous bloomer into a synchronous explosion of color? I am thinking of Tournament of Roses ( a continuous bloomer if I ever have seen one) or most of the Knock Out roses, or lady Ella Mae, or another bonafide ever bloomer, Julia Child? And just as easily (at least in my water and nutrient deprived soil) turned a synchronous bloomer like Queen Elizabeth or Iceberg into a continuous bloomer (but not quite bouquet providing) just by not providing them a quite adequate or evenly applied water/nutrient supply? Large shrubs that provide repeated flushes that are show stoppers definitely will get most peoples' votes as we can see by the popularity of roses such as the Knock Outs, Julia Child, and the Icebergs. Disease resistance is what separates them from the herd.

Re: Synchrony vs. Continuity

Posted: Sun Jan 01, 2017 8:08 am
by Karl K
Thanks for the great observations.

And somewhat strangely, my 'Paul's Scarlet Climber' gave very little repeat bloom in 2015, which was a VERY wet year in my area. I even joked about sowing rice as a lawn grass. This year there was almost no rain during the growing season, and I did not water PSC with any regularity. Nevertheless, the darned thing gave at least 5 big flushes of bloom (if I had known, I would have paid more attention).

In this case, continuous moisture allowed it to vegetate through the season. Drought, to the contrary, inhibited vegetation. The leaves did not drop during the summer, but the forced "rest" allowed pulses of bloom. At least, that's one possible explanation.

I had a hunch that there might be some parallel with annual- vs. biennial bearing of some fruit trees. I did some googling and came up with some interesting info. Of course, most of the reports dealt with preventing biennial bearing by pruning or thinning of fruit. None discussed heredity, because only named varieties were examined.

I did learn that biennial bearing can be an acquired "habit" that is easier to prevent than to cure. Also, a major branch of an apple tree, for example, may adopt a biennial habit regardless of what the rest of the tree does. (My PSC had one long cane that did almost all of the repeating.)

Another tidbit: stress can provoke profuse blooming and fruiting of some apple trees, though the size and quality of the fruit suffers.

If annual vs biennial are analogous to continuity vs synchrony, then one of my assumptions (hopes) is dashed. A biennial bearing apple tree yields more fruit in its "on" year than an annual bearer, but the latter has a substantially greater AVERAGE yield. Even so, flush blooming would be more dramatic, particularly with climbers.

Re: Synchrony vs. Continuity

Posted: Sun Jan 01, 2017 10:41 am
by jriekstins
Stress does have a way of forcing plants into a 'reproduce before you die' from whatever mode. I do not know how many times I have seen plants of many varieties go into bloom whenever threatened within an inch of their lives, even when you know it is hopeless! But yes, it is usually pretty pathetic. However, if you have ever read of the Russian family who fled to Siberia before WWII and when they were down to their last stalk of rye, upon which their lives depended, they managed to bring back the colony to a sustaining crop of rye to enable them to survive, based on that one last stalk. Not that they lived happily ever after. Not the best example, but plants are very programed to give it all, for survival.

Re: Synchrony vs. Continuity

Posted: Sun Jan 01, 2017 1:05 pm
by Karl K
I am fascinated by mass propagation wherever it turns up. Here's one about a single grain of wheat that begat enough divisions to yield 2.5 pounds of grain.

And some other examples, including some roses: ... ation.html

Re: Synchrony vs. Continuity

Posted: Tue Jan 03, 2017 10:58 am
by Karl K
Thinking more on this subject today, I remembered something that occurred around 40 years ago. The Kansas summer was particularly long and dry that year, and a small specimen of Magnolia x soulangeana had shed its leaves. When the rain finally arrived (late Aug or early Sept), the magnolia started into growth again and produced a few blooms.

Then there are the Autumn flowering lilacs that Dr. Lammerts helped to develop. The plants must be kept dry for a while to induce dormancy. Then, when flowering is desired, the roots of the plants are soaked thoroughly for a couple of days. Voila! Autumn bloom. ... ate-lilacs

These lilacs lack the chilling requirement of other varieties, but still need a period of dormancy or "rest".

I don't know that I'm getting any closer to my hope for an inherently synchronous bloomer, but maybe just coming to understand more clearly how the different types of recurrent bloom are connected to dormancies.