I've enjoyed reading the discussion on different rootstocks. I drank the KoolAid for fortuniana rootstock back in 2008/09 and now regret it. The All America Selections Display Garden at Burden Center (here in Baton Rouge) adopted fortuniana and had planted hundreds of bushes on the rootstock. All the plants demonstrated robust growth and amazing resistance to disease very quickly, so it was a dramatic endorsement for the rootstock here. A few other regional display gardens also added large plantings on fortuniana. After a few years of observing these seemingly superb results, many gardeners in our area jumped on board and began reworking their gardens with fortuniana. Unfortunately, this proved to be a big mistake. Fortuniana is indeed a robust rootstock, but therein lies its problem. Within 4-5 years, the diameter of the fortuniana rootstock drastically outpaces the diameter of the top rose at the graft site. The union begins to crack and the cambium comes loose, causing a disconnect between the roots and the top growth they are supposed to be feeding... so the bush begins a quick decline. This negative process appears to be exacerbated by our high humidity and feast/famine rain patterns. The AAS Display Garden began ripping out all of the fortuniana bushes last year and is still in the process of replacement. They have moved back to own-root and Dr. Huey rootstock.
Many of the bushes in our garden are on fortuniana, with some own-root. For the first four years, the own-root bushes were dwarfed by the fortuniana ones, and the bloom production was significantly lower. They suffered from more diseases and required more TLC in our garden. However, after the four year mark, the fortuniana bushes became the problem plants and the roots on the own-root bushes had finally developed enough to provide adequate nutrients for good growth and bloom production. The fortuniana bushes are beginning to drop, and we are replacing them as they decline. So far, the replacements have been own-root bushes, but I would be happy to find some of our desired cultivars on Manetti to give it a try. I'm not averse to adding plants on Dr. Huey rootstock either, but so far every cultivar I've wanted has only been available as own-root (or fortuniana). The cultivars on fortuniana that have crashed so far are: Sixteen Candles (year three), Angel Face (year four), Mister Lincoln (year four), New Orleans Lady (year four), Paradise (year four), Veterans Honor (year four), Brigadoon (year five), and Pop Warner (year five). Saint Patrick, Fragrant Cloud and Moonstone are all currently flirting with the shovel prune.
Only one of the initial hybrid teas in our garden was own-root... Kolner Karnival (Blue Girl) came from Heirloom seven years ago. It still looks scraggly and is stingy with its blooms. Quite a few of the initial floribundas were own-root, and their performance has been fine. All of our own-root roses have responded very well when they receive more fertilizer, so our new strategy is to provide better nutrients for root production in an effort to eventually build better top production. Even if I end up with a garden full of smaller plants, I believe the end result will be more of what we want *for our particular garden*. We want to find plants that can remain healthy for a longer period of time.
I would like to know if anyone in the Deep South has had success with Manetti rootstock. Are there any mail order nurseries currently offering roses on Manetti?
