Most nurseries will start their increase block (scionwood trees) from virus-indexed wood such as from the Clean Plant Center of the NW Clean Plant Center Northwest, Prosser, WA and then have the increase block like the Dave Wilson one below tested regularly to be certified virus-free. Most rootstock suppliers do the same thing, and will certify their rootstocks.
However, they only carry common commercial varieties, and if you want a tree of some obscure heritage variety, it will undoubtedly have latent viruses. You may want to have these trees grafted to M111 or M7 or some other rootstock that isn’t bothered by viruses.
I agree. I was looking at the G935 as a potential “tall spindle type tree”. I have found B9 to be insufficient as a dwarf tree here. Doesnt have quite enough vigor to get the job done in my local climate. I know the owners of two local landscape companies that are both interested in doing the selling and me doing the installation of those systems. I also have enough inquires to sell and install the “tall spindle style” here strictly as a backyard addition, but from my own experience in my test plot the B9 trees arent satisfactory for me. M7 actually might work in our climate for the same application. Going to put in a small mixed trellis of those this year as well for test purposes.
Cummins got their varieties, I believe, from the former Cornell breeding program, at least quite a few of their herilooms. I am going to send them a note to find out if they pay any attention to virus issues. I’m not sure what the law is with wholesalers in terms of requirements on the use of virus free stock. I know Adams has a few heirlooms and all their stock is certified virus free. .
Actually I think ACN even mentions on their website that not all varieties they sell are virus free certified. I think all the stone fruit varieties might be.
I would like to see how you are constructing your tall spindle trellis. The trellis ststems I have now are 6’, 3 wire espalier. I will be trying to construct a 11’ tall spindal system made with oil field pipe for posts this spring.
There is no law requiring the use of virus certified stock, either for rootstocks or scionwood. It increases your market however, and many commercial growers insist on it, and thus most wholesalers prefer to deal in certified stock, especially if they ever hope to export. Any imported scionwood coming into the USA must go through virus indexing, malus comes through USDA-APHIS at Beltsville, MD, and then is curated at the Geneva USDA. Thus, the Lady Williams imported from Australia that is at USDA Geneva is assumed to be virus-free.
@alan, I have Dabinett on G.202 that was from Cummins that has a graft union bulge and very sluggish growth. Browns Apple on B.9 about 10ft away and in the same conditions as far as soil and water (wet) and management is many times more vigorous. My thought was always too wet of soil but it doesn’t explain how one tree out of 4 in the wetest part of my yard does poorly and the others are fine.
Here in the northeast I’ve not seen great advantage to using the Cornell rootstocks because fireblight tends to be more of a nuisance than an existential apple issue. I’ve lost a couple pear trees over the years, but not a single apple to FB. The majority of trees in my nursery are on 111 and the majority of my customers have plenty of land- I keep a few trees on 26 if any of them want ornamental espaliers or use pears that can be kept on a small tree no matter the rootstock- such as Harrow Sweet and Asian types.
For customers that don’t fence out deer, vigorous, free standing trees are the ticket. And when you plant one, it is a legacy- one that you can graft anything you want onto.
Assumption is just that. Also I dont see how you can positively be sure the tree is virus free if grown in close proximity to other trees that are NOT verified virus free unless you test it every year before propagation. Which for anyone other than the largest commercial nurseries is not a deal breaker.
Mine are currently 4 wire, with the tallest wire at 10’. 3’ spacing between trees. The height is an issue as well as I would assume it will be for you at 11’, due to our “calm” prairie breezes. Though a site with good wind protection shouldnt be as negatively affected by the wind. I wind strongly recommend vertical supports for those trees until they are established at the final height, I think 1/2" conduit is probably the best choice. I tried a vertical guide wire only and have had too much damage to leading terminals from whipping in the wind.
What kind of posts are you using and were do you get them? I don’t know where to find 14’ or 15’ post locally besides cutting hedge or trying to find old oil field pipe
After I thought about it some more my top wire is at 9’. Mine have been short enough runs thus far (just testing concept) that I used a 4" x 6" x 12’ treated post on each end set 3’ into concrete. Ran all my wires through the posts and then to an in ground auger type anchor. Each line has an in line tensioner to tighten the lines. The next ones I build will only have the top line running to the anchors and the other lines dead ending on the post with a tensioner tied to the post itself and not the anchor. Mine are currently 36’ between posts, 10 tree runs. If I ever decided to make longer runs I would go with those treated landscape type timbers every 20-30’ I suppose between end posts. I used 12 ga wire for my lines and that seems adequate to me at this point.
My impression was G16 was the only Cornell rootstock with serious virus sensitivity issues. I found that out after parking various buds on the trees from Botner wood and I think I killed most of my G16 trees that way. I have about 10% of them left now.
