Thornless roses-what defines them?

What makes a thornless rose? Is there an upper limit of thorns (or prickles) or occasional thorns that disqualifies that description? I have never grown a ‘smooth’ or ‘soft’ rose and I am curious about that description. I have gotten several nice disease free ‘almost thornless’ seedlings, and this year have what appears to be a large flowered climber(semi double, 10 petals) that is totally thornfree, and they are so nice to handle; even the petiole is pretty much prickle free. Is anything known about the dominance (or not) of thornlessness?

Great questions.

Thornlessness in diploid Rosa multiflora based material (polyanthas and rootstocks) is recessive and is based on stem prickles. They typically have prickles on the rachis (petiole). Dr. Bryne and others reported thornlessness in a cross of Basye’s Blueberry and another rose. In the end it seems like the prickle free character was independently inherited between the stem and rachis.

It seems like thornlessness out of Little Darling (although it is thorny) in the Smooth series by Harvey Davidson and many minis may not be simply recessive.

Degree of thorniness among thorny roses is quantitatively inherited and there are Quantitative Trait Loci identified.

Sincerely,

David

So—are thornless roses totally thornless, or are there a certain amount of thorns allowable? Or is this not really a definable quality?

I don

I think NONE on the canes NOR rachis (the underpart of the leaf petioles) could be defined as completely thornless.

I would agree with all of the above that has been said. I have mentioned it before but someone gave me 2 plants of Veilchenblau which had sprouted from the roots when he dug up and moved his original plant. I didn’t believe they were Veilchenblau since they were moderately thorny. So I planted them at the far back of the property. They grew and the canes had thorns. By year two, some canes were coming up smooth and now they are basically all smooth. Sometimes as Paul says, it will through a cane with thorns.

I have a rose plant that sprouted by a pole. A bird must have gifted me. It grew up to about 5ft high, healthy as hell, has fringed stipules and the blooms are a bit larger than multiflora and a light pink with a white center. Last year it bloomed for the first time and it looked like an anemic “Ballerina”. Small and very narrow flower petals. This year the blooms are a bit larger than pure multiflora and still have the pink on the edges. It is completely smooth including the rachis though one cane last year came up and had thorns on it including the rachis. My gut feeling is that there must be some physiologic change that causes the plant which is normally smooth to revert to thorns, etc.

My Tausendschon is generally totally smooth including the rachis.

While we are on this topic, In one of Karl King’s articles on thornlessness, one of the writers did an experiment (granted with small numbers) and he found if only the mother was thornless, more of the seedlings were thornless and vice versa, if only the father were thornless, fewer of the seedlings were thornless. Has anyone found this to be true???

This is getting to be a pet topic of mine; and getting to be a prime criterion in my selection of roses.

Warren, you have been breeding for thornlessness. What are your thoughts and what have you noticed? I have looked at your crosses on HMFR and notice some of your parentage are “armed with thorns” but will still throw an F1 or F2 thornless plant.

Jackie, I am sorry if I digressed since you were asking more for a definition. I notice HMFR lists such roses as “thornless or almost thornless” which makes it broader if you are doing a search for thornless roses though some of the profiles will list a rose as completely thornless which I assume to be canes and rachis.

I also believe I have read that if one makes cuttings from a cane that has fewer thorns on it, and repeats the process, one can end up with the same variety but smoother caned in time. Don’t have any personal experience with this.

Jim

Jim,

Thanks for your observations, and experience. My only experience has been with a relatively thornless Moondance, which has had a fair number of thornless offspring. And I have read opinions (or critiques) of Moondance that have opined that it is too thorny of a rose to work around. I use a little path through my roses to get to a lower level going by Moondance because since year one, it has produced so few reach out and take off your clothes type thorns. And when it has been paired with another nearly thornless rose that I have, it even produces more thornless or nearly thornless seedlings. This is reaching into the 2nd generation with even less thorns, so now I am getting interested in ‘thornless’ or pretty low thorn factor roses. The seedling that I have with no thorns on the stems or rachis is from two moderately thorny parents.

Paul and David,

Thanks also, so the takeaway on this is that thornless is not always thornless, and there is little actual criteria defining thornless, and sometimes a thornfree shrub will revert to thorns. I definitely am interested in anything that will lessen such a prickly subject-a bit of an age factor here, I’m sure.

Jackie, I don’t know whether they’d be the types of roses you’d be interested in, but these do make thornless babies.

Little Darling and its offspring, 1-72-1, Rise’n Shine, Cal Poly, Golden Gardens.

Basye’s Legacy and its offspring, Indian Love Call, Lynnie, My Stars.

Other thornless, or nearly totally so, roses in my garden include Cl. Yellow Sweetheart (found ONE prickle on the fifteen gallon plant when moving it this week); Pink Gate; Annie Laurie McDowell; White Renae seedling; and of course Purezza and Banksiae. Renae is thornless and produces seedlings totally without prickles. Kim

I cannot recall any prickles on my old, now abandoned Rosa bankisa lutescens (the single yellow).

Nope, that one is thornless. The only one I’ve ever really seen prickles on is the single white. Neither of the two doubles have exhibited prickles in my experience. Kim

Yeah, I do remember the yellow banksiae as being pretty thornless, and really really lanky. I plant them all the time for clients, but I just do not have that big an area to dedicate to one rose. I went out and examined most of my seedlings that are at least 6-8" tall or have produced multiple stems, and the one group that has multiple (I segregated about 10-12 pots)seedling offspring that so far are thornless, except for a few on some of the rachis, is a Gemini X Summer Wine cross, with both of the parents being moderately thorny. I do have the other half dozen thornless 1-3 yr olds that I now want to see what they will produce. I have Cal Poly, but have never used it because it spends most of May-June in a fog of mildew. And the thornless wichuriana I recieved from you this spring is budding up right now. That plant looks like it is on some serious growth meds. Wichuriana should take with something I cross it with, right? Just for the sake of thorn free offspring I will try it with anything that has produced or is thornfree now. I admire those taking forays into other complicated and long term crosses with few chances of quick success, but I think I will stick to something that I might see some results from in my own lifetime.

Jackie,

I can offer you some pollen from my 34-06-05 if you’d like. (See HMF link) It is 100% thornless at all times, and highly fertile. 95% of its offspring in all tests I have done have been totally thornless also. It has the added advantage of passing on its bicolored trait: red on top and soft yellow on the reverse.

Link: www.helpmefind.com/gardening/l.php?l=2.59114

Paul,

I LOVE that rose. In the middle of a move but later hope it will be offered for sale. Glad you put Little Butch (almost wrote Little Bitch LOL) on the market. Hope to buy it next year when I am settled.

Jackie,

I looked up Moondance. There is confusion because there are 2 separate roses with the same name (HATE when they do that) According to HMFR, The Meilland Moondance is an Apricot HT and described as being “armed with thorns.” The othe Moondance was introduced a few years later and is a J&P Zary introduction. It is a White floribunda and is described as “almost thornless” with Iceberg being one of its parents.

In the comments section under the Zary Moondance, someone refers to its many wicked thorns. Either the plant is a fluke or they meant to write the comment in the other roses profile.

I checked my smooth caned Veilchenblau today and the rachis has little prickes on it, quite regularly. The Tausenschon on the other hand does have them but fewer and smaller.

Jim

PS- Where is Warren, our smoothie expert!!!

Jim,

I’m glad you pointed out the listing for “Little Butch”, because that is an error! That seedling has NOT been set up for commerce at all yet. I have no idea how that information got into its HMF listing.

The thornless bicolor, on the other hand, is almost certainly going to be released in the next year or two.

Paul,

Would I like some pollen from 34-06-05? Absolutely! That is such a great trait-having no thorns on the mid rib. I don’t think I even considered getting excited about thornlessness until I realized that was a possible trait. The thornless wichuriana really grabs for keeps with just those tiny rachis teeth. I will shoot you an e-mail with 34-06-05 in the subject line. That is an exciting color, which I am getting something similar with Rt.66 X(MoondancexAbout Face) They are really healthy and on the petite side, but they are also just new seedlings. I have an exceedingly floriferous Moondance x About Face that is quite large, but produces these really small plants.

Jim,

I did see at least 3 references to Moondance being excessively thorny, and one of those may have been referring to the Meilland product, and one of the references was in the comments about Zary’s Moondance, so it did not occur to me that that might also be a mistake as you pointed out.

Howdy Jim,

The data in HMF has been corrected regarding thornless or almost, when I submitted roses for registraton here in OZ, I wrote has a few thorns which I meant not (overly thorny) and was interpreted as thornless or almost.

I have been breeding for thornless over the last couple of years, results are looking promising. Have been using Smooth Buttercup, Vanilla (thorns are only down at the base). Using Blue Moon, seemed to produce some offspring with little or no thorns and with a big bonus of its scent being transferred to the offspring.

I have at home a Charles Austin which is’nt overly thorny , compared to what I have seen in other gardens. This CA when crossed tends to give thorns only down at the base, and when crossed with Smooth Buttercup, thornless.

Here is something of interest, I crossed Safrano with a climbing Gold Bunny, the results were, 4 offspring I kept. One was completely thornless, two almost thornless and one armed to the tooth and a climber.

At the moment I have 7 lines of thornless and an other thornless rose bought in to cross bred. I dont know what will happen, maybe smooth sailing or a prickly one.

Let’s not forget ‘Commander Gillette’ (I believe this is the same as Legacy), which is not only thornless, but richly fragrant, vigorous and nearly disease free. Pollen available in the next week or so, if desired.

Paul

We didn’t, I listed Legacy which IS Commander Gillette as all the Basye’s Thornless, Commander Gillettes, 65-626, 77-361 and Basye’s Legacy are identical. They ARE the same roses. Dr. Basye identified the same rose twice as two different ones. The only other thornless species cross of his around is Blueberry and in my experience, it doesn’t pass on thornlessness. No one else mixed it up. The good Doctor did it his own danged self. Scroll down to the 4/27/10 comment. Kim

Link: www.helpmefind.com/rose/l.php?l=1.18629&tab=32

Kim, my OP 88-390 seedlings, from (supposedly) Bayse’s Blueberry’ x 80-358, are thornless. Maybe Blueberry can pass on thornlessness as 80-358 is from Dr Basye’s tetraploid hybrid bracteata line which, knowing bracteata, is likely to be quite a thorny line itself.

I have raised only a few OP seedlings of Basye’s Blueberry,

and so far all have been thornless, disease free, and non-

suckering. Flowers have been singles or few petaled doubles

in about equal amounts. Color has lacked the maroon tinge so

typical of R. rugosa hybrids–mostly soft pink, one sort of

salmon pink, and a single pure white. The hips did not color

until very late–some were picked December 24, 2007, with a

few more gathered about three weeks later. The result was

sixteen plants, with ten remaining May 2011. Five are less

than eight inches tall, the most vigorous is about eighteen

inches tall.

My present assumption is that these are tetraploid, and should

be crossed with a more vigorous, and possibly more double rose. Fragrance hasn’t been noticeable. It appears that BB

will allow a broad color range in its’ descendants.

Ken in sunny Oregon, where the sunshine is so concentrated that it falls in drops of liquid.

I didn’t raise any selfs from Blueberry, but nothing I’ve ever mated it with produced thornless offspring. Nor were any of its seedlings as trouble free as those from Legacy, so I concentrated more on Legacy. At least in my climate, disease resistance is far more necessary than cold hardiness, so the benefits of Virginiana and Arkansana are lost here. Hybrids of both, with the exception of Morden Blush (THE most bullet proof of all the Morden and Explorer roses here), have been plagued with rust and black spot. I LOVE Blueberry as a destination, but as a tool to a further destination, it just didn’t show that much promise in my hands. Kim