Tweaking thinking

After a few more emails and questions, the thought occurred to me that presenting these ideas may make this a bit more logical to readers, so here goes!


Why should wrapping cuttings and maintaining them in the lower temperatures work better?


First, remember the instructions on packaged bare roots about mounding? The idea is keeping the plant cool, dark and damp stimulates the formation of roots instead of top growth. Absence of light and heat combined with dampness is what roots grow in. Adding heat and light stimulate leaf, cane and flower bud growth.


Wrapping the cuttings in damp paper simulates damp earth, as does the darkness. Keeping them cooler prevents formation of the chemicals which trigger top growth, favoring the formation of callus and roots instead. The cuttings already contain the programming to form callus which further develops into roots. Providing them the appropriate conditions to favor that kind of development speeds the process along. Holding them in higher or warmer temperatures stimulates both growth and callus, often the former at the disadvantage of the latter.


The whole reason for the rose to grow is to create flowers. The whole reason for the creation of flowers is to attract pollinators to create seed and perpetuate the species before the plant dies. Pollinators and the plants evolved together. The more successful roses broke into growth and flower as the appropriate pollinators arrived. Both were stimulated into the appropriate state of development simultaneously. Providing different conditions than those outside "trick" the rose into doing what is wanted from it, much like the Romans passing steam under potted roses to force them into flower out of season. Also, much like forcing Paper White Narcissus into flower earlier than usual for the holidays.


If your temperatures are already higher than the suggested sixty to almost seventy degree temperature range which I've found beneficial, why not wrap them, and presuming you have enough room, put them in your vegetable crisper? Prevent them from freezing, of course, but the cooler temperatures in the fridge should also stimulate callusing, though probably at a slower rate. Rose roots continue growing in near freezing soil. Not as quickly as they do in warmer soil, but they do still grow. You might find the need to hold them for three weeks at the lower temps than is optimal at the upper end of the suggested range. Only experimentation will determine that.


I've been repeatedly asked about my potting soil. I have some humidity and more than a little heat. Though no where near as extreme as many other places, it does get HOT here now. The evaporation rates are quite high, yet the evenings remain cooler and even with the heat, it is still humid enough to rot plants sealed under plastic or inside a terrarium. For these reasons, I use moisture control potting soil. If your humidity is greater so evaporation is slower, that man remain too wet for the conditions, rotting the cuttings. Many years ago when propagating for The Huntington Library as a volunteer, using their mist propagator, we used half coarse builders sand and half perlite. It remained damp after the water drained through it, but it also had a lot of air space in the mix so the cuttings didn't rot.


I've known people who tried to replicate the mist propagator and failed because of using organic based soil mix. Continuous wetness causes organics to sour. Dampness works, constant watering, doesn't. The wetter and more humid it is, the more open and fast draining you need your soil mix to be. Same holds for cool temps. Hotter and drier makes for greater evaporation, hence greater water holding capabilities.


It's dramatic the difference humidity makes. My old climate had none (usually) and required keeping everything covered in plastic or they'd die nearly immediately. Here, covering anything in plastic results in it molding nearly immediately. I've never been able to just stick any kind of cutting in a pot in the shade and have it root, but I've done it with hibiscus over winter. I'm going to mess with Mutabilis this winter attempting the same thing. I figured I'd have to put callused rose cuttings under plastic once planted out, but they're forming roots with half day full sun in foam cups. That wouldn't have happened in Santa Clarita. But, then, I never had the fungal issues there I have here, so the humidity is far different. I can FEEL it here, I couldn't there 99% of the time.

The best way is to get a handle on your humidity and how it varies with the year (presuming it does). Surf and absorb all the various methods you find explained and develop one combining the best of all of them, tweaked to your heat and humidity, then begin experimenting with it to see how it has to evolve to work where you are with what you are trying to propagate. 

Once you figure out your humidity and evaporation rate, you can determine what kind of soil is best for you to use. You can also decide whether or not you need to cover the cuttings once callused. I'm finding planting them deeply in the soil to maintain cooler, damper, darker conditions, is working quite well without rotting or drying out before rooting. Think of the cutting in terms of a bare root plant as they really do require the same conditions until they form the root system necessary to support the leafed out plant.

Progress and assorted thoughts on wrapping

After some discussions on Garden Web and a few private emails, I thought it might be of interest to share some further thoughts about wrapping and show progress of the China rose cuttings which were planted just ten days ago (June 11).

It's guaranteed this will require tweaking to be as successful as it can be in other areas, as does anything else related to gardening. I'd originally felt thicker cuttings were going to be more successful. That doesn't explain the 18 foam cups of China roses (really thin, twiggy cuttings, some a quarter the gauge of an eyebrow pencil)  pushing roots out the bottoms of their soil balls. It also doesn't explain the thin cutting of Escapade developing nicely into a maturing plant in a pot.

I do tend to try to make thinner cuttings longer than thicker ones and that appears to have helped. The China cuttings are all five to seven inches long. For any new shoots sprouting from them, I just cut them off leaving the side buds alone so there isn't a lot of softer growth. The "joints" and increased growth buds appear to help, like the traditional "heel" always suggested to take with cuttings with.

These images show cuttings in 16 oz. foam cups followed by each one's roots at the bottom of the soil ball. Clicking on the images enlarges them for more detail.

Chinas can be difficult to select wood to cut for propagation. There are so many "joints" with new growth pushing out everywhere. I selected wood I could cut the five to seven inches of growth. Any buds which had pushed leaves or new canes, I simply trimmed off, leaving a few growth buds on the cutting so new growth was possible from that sprout once rooted. Some of the trimmed, newer growth actually callused and formed roots. Buds which had begun to push and form new foliage were also trimmed so there was no leaf tissue to rot in the damp paper.

Genetics definitely play a role as some just don't have the genetic ability to form callus well nor to form roots which will support the plant efficiently. Shadow Dancer has been a difficult one to encourage to callus and root. Gauge of wood doesn't seem to matter, nor does cutting length. What has rooted most easily are the actually flower clusters where you traditionally don't expect to find growth buds.

The level of stored nutrients available in the cutting will probably also help determine success. Any pathogens already on the cutting when wrapped should also play a part. I'm not sure how wide the successful range of moisture there is with the paper, but too wet WILL cause failure as they suffocate, drown, rot. I haven't experienced what I might consider too dry yet.

It appears temperatures higher than the sixties degrees F range to hold the wraps are too high and inhibit callus formation.

As I've collected the cuttings, I have dropped them into a bucket of water to hold them until I was ready for processing and wrapping. Perhaps if they are too dry when wrapped, that might play a role in failure? I collected, cut, stripped foliage, bundled and tied together with twist tie with label strung on the tie, then dropped the bundle into the water where they waited for collection to finish. Then, I'd shake off the water, dunk them into the Dip'n'Grow and wrap. The wrap would then go into a plastic bag, sometimes several together, and into the work room.

I haven't tried any really soft cuttings yet. My impression is they would benefit from mist propagation to prevent them from collapsing or rotting where harder wood, perhaps better described as hard wood cuttings, seem more appropriate for the method.

Traditionally, you'd use a flowering stem from a recently shattered flower for propagation. I have used that with the wraps and they have worked. I've also used wood older, more mature than that and that has worked. I haven't used anything newer or softer than that with it. They have just 'felt' too immature.

If it's difficult to squeeze out enough water from the paper, try an old rolling pin you wouldn't mind getting printing ink on. That might  provide a make-shift wringer for your paper. You should be able to squeeze out even more water than possible by hand, and it should be a lot easier on your (MY) hands!

Observations

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I remember when I first read water stressed roses can mildew even when conditions weren't necessarily right for causing an outbreak, and thinking how odd that seemed. I've observed it time and again, and it makes sense.

More discussion about plants immune systems have taken place on the Rose Hybridizers Association and Garden Web, and it is actually pretty logical. If any organism is stressed either through lack of water, inappropriate heat or light, drainage, physical trauma, malnutrition, etc., it becomes more susceptible to attack from disease. Its immune system is weakened allowing opportunistic infections to take over much like with a human when weakened by long-term illness or malnutrition.

What gelled this thought for me is a potted plant I have of R. Arkansana. The species is known for being susceptible to rust infection later in the year. It appears to be one of Nature's triggers for the plant to begin storing food to go deciduous, making it more cold hardy.

My plant has suffered from rust here in Encino most of this year. It seemed just as soon as new leaves formed, they began to rust. The pot is probably too small for the plant and it sits where it receives sun much of the day, causing it to water stress fairly quickly. However, once the idea began to gel, I began paying better attention to keeping it watered properly. Not surprisingly, the new foliage being created is not only larger, but it is also healthy with no evidence of rust.

Permitting it to dry out seems to have mimicked Nature's not providing it with sufficient water in late summer and fall, causing the foliage to mature into its "old age" phase when it is most susceptible to rust infection. Rust causes what we consider premature foliage fall, but Nature's use for it is to cause the foliage to drop so the plant hardens off so it survives winter. I've been "confusing" the plant into thinking it should go into winter preparation mode, even though its growing season hasn't really happened yet.

I'm sure climatic suitability plays a part in the rust issue, too. I had observed in my old Newhall garden that Arkansana hybrids, except for Morden Blush, which was one of the most bullet-proof roses in that garden, weren't climatically suitable as they rusted very early in the season and continued rusting even when nothing else suffered the infection. A few of the Buck roses, notably Wandrin' Wind, suffered from extreme rust there, also.

Oddly, R. Arkansana "Peppermint" isn't affected by rust at all. It is planted in the ground about ten feet from the potted Arkansana, but it suffers from reflected heat and light off a white vinyl fence and has to battle asparagus fern and the resident mole, yet it grows cleanly and even flowered this spring.

Much has been written for a long time concerning the black spot susceptibility of roses bred from R. Foetida. What makes the most sense to me is genetic confusion.

Foetida is a deciduous plant. It has evolved where the greatest success requires forming its foliage early, using it up quickly, appropriate for the short growing season are it evolved in, then shedding it to prepare to winter without damage. We mixed these genes, with their associated immune system, with ever green genes from Tea and Hybrid Tea roses, which evolved in very long growing season areas. What resulted has been a line of roses which are genetically confused, with confused immune systems. The plant has instructions for creating its foliage quickly, using it up quickly so it may be shed to prepare for winter, combined with those telling it to hold that foliage the entire season. What results is foliage which quickly matures through its juvenility, rapidly becoming "senile", elderly, on a plant which refuses to shed it because the genetic information tells it to hold them like Teas and HTs do for longer growing seasons.

Rust and black spot are senility diseases, attacking "old" foliage to cause it to drop from the plant. The roses bred from Joseph Pernet's work with Foetida, those with red and yellow bi colored petals; brilliant yellows, oranges, scarlets and their blends; roses in 'tropical' colors such as shrimp, flamingo pink, "Peter Max" poster paint, neon colors, have this information programmed into them. They are the ones notorious for black spot and sometimes rust, infections.

The plants quickly form "senile" foliage, susceptible to the particular fungal attacks, much like my water stressed R. Arkansana is experiencing. We unnaturally selected roses with confused immune systems, and continue to attempt to select the better examples of that confused line in hopes of eliminating the confusion and producing healthy plants with the colors we desire. What we experience may well be not only what the plant is genetically programmed to do, but also what we unwittingly tell the plant to do through our culture, or lack of it.

New American Hulthemias due out 2012

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Hulthemia, a xerophyte native to desert regions of Iran, Afghanistan and Turkey, called "the most noxious weed in Iran" and desirable because of its characteristic red 'blotch' petal base. It's one of my prime rose "obsessions" and has been for over twenty-five years.

Rose petal bases are traditionally white or yellow. Hulthemia's is a deep, rich brick to crimson red on a bright yellow petal. Jack Harkness created four garden hybrids in England in the late 1970s and early 1980s. His company has much more recently introduced other hybrids of their breeding. None of which are available in the United States.

Mr. Harkness was a friend of Ralph Moore's, who took Harkness' work much further with his Hulthemia hybrids. I had the pleasure of suggesting the "Persian" series for their names, which is why all but Roses are Red have names beginning with Persian. I thought it appropriate because of where the species is indigenous and because two of Harkness' hybrids were named for major rivers in that area, Tigris and Euphrates. A third was named for a Persian ruler, Xerxes. The forth of their original garden hybrids was named to honor the British actor, Sir Nigel Hawthorne. I've grown all but Xerxes, which, unfortunately, appears extinct.

Mr. Moore took Hulthemia from the spring blooming only, small flowered bramble plant of the British hybrids and added vigor and repeat flowering. His Persian Autumn, Persian Sunset, Persian Flame, Persian Peach and Persian Light were introduced by Sequoia Nursery before his death. Some are still available today and are worth growing in more arid, hot areas.

Another friend of Mr. Moore's is a gentleman by the name of Dr. Jim Sproul. Dr. Sproul has worked with Hulthemia for over fifteen years, raising thousands of their seedlings each year at his Bakersfield, California home. Jim has created some very interesting, quite beautiful roses in addition to his Hulthemia hybrids. His web site, Sproul Roses is well worth browsing and following to keep up to date on his imaginative work.

Spring of 2012 sees the introduction of three of Jim's creations by Star Roses. Thrive! is a disease resistant landscape shrub bred from the Knock Out line and should be quite a good addition to the healthy landscape rose segment. His two other creations are what have me really excited!

Jim has taken the characteristic Hulthemia "blotch" and put it on real garden roses! Instead of the wispy, prickly "bramble bush", Jim's roses are real garden rose type plants with much more traditional foliage. One of the pre release plants was sent to me by a nurseryman friend, and I am impressed!

Star has created the marketing label "Eyeconic" for them to capitalize on their Hulthemia "blotch". Eyeconic Lemonade is a floribunda shrub with large, yellow with red blotch center, wonderfully fragrant flowers.

Eyeconic Pink Lemonade is similar only with pink flowers with red blotch.

The foliage on Eyeconic Lemonade is absolutely gorgeous!

So far, and it is still quite early, there are no issues with it here in Encino. Not bad for a plant which had sat in a bucket of water far too long, even began leafing out in that bucket before being mailed to me. It's just been here a few months in a two gallon can and you can see how very nice a plant it is!

Until now, Hulthemia hybrids had thin, wispy, prickly wood. Not Eyeconic Lemonade! These are thick, sturdy stems nicely clothed in very nice foliage. There are prickles but nothing like its predecessors.

If you like becoming familiar with something new, watch for Eyeconic Lemonade and Eyeconic Pink Lemonade this coming spring when Star releases them in the US. Good job, Jim! VERY good job!

Further Warmer Weather Wraps

As I explore and experiment with this method of rooting, I'm impressed how crucial the level of moisture in the newspaper is. It must not be wet, but DAMP. You need to squeeze as much of the dripping water from it as possible or your chances of rot are significantly greater.

I've also found that the apparent optimal temperatures to hold the wrapped cuttings under is in the sixty degrees F range. Hotter and they will attempt to sprout leaves instead of callusing and rooting. Other than to use refrigeration, I have no way to test colder temperatures, but the success rate in the sixty degree F range is sufficient to not encourage me to try colder.

I wrapped two burritos of unnamed China roses three weeks ago. After two weeks, the first wrap was callused and it has been planted. Today, three weeks after wrapping, this bundle came out. Remember, you may click on any image here to see the larger version for better detail. Click on the enlarged photo for an even higher magnification.

The storage room where I'm keeping the bundles now is slightly warmer due to the increased temperatures outdoors. It is still well within the sixties optimal temperature range, but it is warmer than with the original results. You can see the range of callusing to actual root formation. These were planted this evening and watered in well.

Two weeks ago, I wrapped this bundle of the climber Shadow Dancer to see how it responds to the method at this time of year. These were the results tonight after two weeks at the slightly warmer temperature. Notice the best root formation is on the actual flower cluster. I had been taught that the actual flowering cluster wood wasn't suitable for propagation due to the lack of growth buds. However, I experimented with my Annie Laurie McDowell and several floribundas before testing this variety and have found throughout the initial experiments, this "unsuitable" wood is the fastest to form calluses and the most likely to actually form roots in the wraps. And, from experience, they DO have growth buds and will make use of them once sufficiently rooted.

With varieties such as polyanthas, most of the available wood for propagation ARE these flower clusters. Most polys don't form that many nor that long shoots with growth buds and foliage to cut without taking large sections of the plant. By using these cluster shoots, too, you increase the quantities of the plants notorious for throwing these growths you may propagate in a season, and you will likely find these are the ones to propagate fastest and easiest.  To illustrate, this is an earlier piece of a climber I wrapped and which rooted quickly. Traditionally, this is the type of wood I was taught wasn't suitable due to lack of growth buds. As you can see, it has buds.

As a further experiment, I treated and wrapped cuttings to send to a friend in another state. She wouldn't be ready for them until after June 9, so I prepared them in time to mail them and have them ready for planting a day or two after receipt. She emailed to say the thicker cuttings were nicely callused when she opened the burrito. The thinner ones weren't callusing, but turning black. It appears this method may be better suited to thicker, heavier growth with some varieties. As you can see from the above photos, at least for China roses, the gauge doesn't seem that important.