Viewing post #1026008 by RoseBlush1

zuzu said:There are a couple of misconceptions here that should be cleared up. Own-root roses really have nothing to do with Knock Out roses, although it's true that Knock Out roses do grow well on their own roots. An own-root rose is any rose that's grown on its own roots instead of being grafted. Keith's seedlings are own-root roses.

Grafting doesn't make plants hardier or more disease/pest-resistant. The rootstock might be hardier or more resistant, but the rose itself will retain its innate qualities. This is the reason that the Dr. Huey rootstock is more likely to take over in colder zones. It can be hardier than the rose that's been grafted onto it. Grafting can and does add vigor to most roses, and this is the reason that so many roses were always grafted until recently. Many hybrid teas, for instance, will not grow well on their own roots because they aren't vigorous enough to grow large and to produce many blooms.

Zuzu ... you are so right about root stock having little or no impact on disease resistance.

Even in the early 1800s roses selected to be sold were grafted just because that was the fastest way to bring multiple plants to market, not because of the additional vigor supplied by the root stock.

After WWII, if a rose was considered to possibly be a rose that would sell, the test rose was immediately grafted to root stock so that it could be grown in the fields for further testing. Once a rose was selected for distribution, the roses were grafted to build up stock for large distribution. Again, the purpose was not to add vigor to the rose, but to create inventory for sale. So many roses, had they been tested own root would have never made it to market, but as you pointed out, the root stock did add more vigor to the rose and made the roses more garden worthy.

I can't say the whole class of HTs lacked the vigor to grow well own root, because there are too many variables at play. (I have seen some monster own root HTs.) However, I agree many have benefited greatly by being budded to a stronger root stock.