This is good information Ann. Thank you. I guess that's why it pushes bigger blooms in warm places, no dormancy? Makes sense.

Stillann,

Do I understand you correctly.....fortuniana grafted roses will send up crown growth or lateral growth in the winter when it's below freezing? I must be misunderstanding?

How did your own root R. Fortuniana survive? Did it not behave the same over winter as, say a hybrid tea grafted onto fortuniana?

Moses

I have read from K&M instructions that Fort needs dryness to go dormant.

Thanks, Ann. It's helpful to hear about your experience. I knew that fort is useful for an understock only in warm winter areas but didn't have a clear idea where its limits were or why. For so many plants, I think that I am on the edge of where they can be grown successfully. I think that I would be for this rootstock too, depending on how hardy the scion is. I gave up on roses grown on rootstock but thought I might try it again with some overly ambitious spreader. I wondered how it would fare on this one.

Kes,

it's going to depend on which valley in east Tennessee you are in and how much top soil you have. We have a whole range of valley soils in east TN. I'll take this to a different thread.

Stillann,

So, the vigor of a fortuniana rootstock pushes the scion to shrug off winter in a negative way. It keeps the scion always on a moment's notice to start growing at the least warm spell in winter. Then when the weather turns colder, the initiated growth gets damaged, subsequently diseased, and then the whole scion declines from fighting disease. This occurs repeatedly all winter long, taking its toll on the bush. Is this right?

Moses

Stillann,

What do you think of these two scenarios, used in conjunction or individually:

1. Plant the graft down 4". If the rose does repeated false starts all winter long, at least the crown is protected from cold, and the canes only are false start damaged. In early spring at pruning time all the above ground cankered canes can be cut down to ground level. Then the vigor of the bush will cause rapid recovery, and fresh basal breaks from the healthy crown will quickly rebuild the bush.

1. 2. Come fall, when the flowering season is over, root prune the in ground fortuniana grafted rose all around a 6" perimeter from the crown using a root pruning spade. This will theoretically weaken/shock the bush enough to stop top growth, but not enough to permanently harm the bush. Along with winter cold, the bush will slowly, recover, and not push out false start growth. Come spring, the bush will be recovered and grow normally.

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In your opinion, would either of these practices work?

Moses

2 more than 1.

Maybe.

From watching fortunianas in other peoples' gardens, I think this is the way they work.

First you get a new cane. It grows a terminal breath taking bloom, which we enjoy and then cut off.

That causes the next laterals to push new canes with terminal blooms. That first cane doesn't lengthen, but the laterals bloom higher than the previous bloom.

Then the next batch of laterals let loose, and on down the cane.

What I think may be very important is those lateral buds that are so often overlooked at the very base of a major new cane. The ones that are much more closely spaced (fractions of an inch) than the ones five inches or so out the cane. The laterals that often are accompanied by a very subtle horizontal line that goes half way around the cane. The laterals that if they push a leaf at all, push a leaf that is mostly stipule and almost no terminal leaf and never a compound leaf. These drop off. But I think with scions on fort. these very basal most laterals are going to be the source of the major canes in years to come. Because, if I'm right, these have to be protected at all cost.

If the scion base is buried, those lateral buds, having vibrantly healthy meristemic tissues, are going to become roots because they are underground. I think that is why it's important to keep the grafted area above ground.

I've wondered if the shapes of the pots should be more like 40 gallon drums cut in half. Or even thirds with the middle third thrown away. And painted white to keep the temperatures colder in winter months. Then black come summer.

I've even wondered if bubble wrap would be an acceptable insulation, Wrapped so it would look like the Michelin man tire advertisement. I could bore you with my attempts to winterize and how most of what I tried just made better growing conditions for canker.

The other thing would be a rap a and hat. Gertrude Jekyl in several of her gardening books has sketched by Markeley showing a protection for rose standards (as opposed to rose dwarfs on much shorter 'stems'. What they (G and M) thought was important was to deflect snow, ice and water from the graft up in the air. For all the world, what they made looks like a decorative broom, lost so long twigs, maybe rushes, tied together at one end, but not around a broom handle. The sketches look like the pointed end of a witches hat, without a brim. (You may be able to download her books via Google.) This might help your idea #2 work.

Ann