I have never tried to tackle a mess like that, but here is how I would approach it. First and foremost, you need to know the difference between 1 year old wood and older wood. 1 year old wood is smooth, light tan in color, and usually 3/8" thick or less. Older wood is dark brown, rough looking, gnarly and thicker. You also need to have a handle on these terms:
- Trunk : part of the vine that runs from the ground to the trellis wire. Probably older wood
- Cordon: kind of like a horizontal trunk. Part of the vine that attaches to the trunk and runs along the trellis wire. Often older wood, but might be smooth 1 year old wood.
- Cane: the entire length of a 1 year old shoot
- Spur: What you have if you cut a cane down to a few buds. You might be able to identify old spurs. they should look like 1 or 2, or a mess of canes emanating from the old cordon.
- Sucker: cane emanating from the ground or trunk well below the fruiting wire.
- Head: the area where the trunk and cordon meet.
- Spur pruned vine : Vine that consists of a cordon formed from old wood that has spurs every 6 inches or so.
- Cane pruned vine: Vine that has been pruned to have a cane laid down along the wire.
- Node: Nodes are kind of like highway intersections where interesting things happens on the vine. All buds are located at nodes. If you trace a cane back to where it began, that is a node. There is usually a node every 4-8 inches of vine.
- Internode : Straight runs of vine between nodes.
Ok, so here is my approach (reminder, I have never done this).
Step 1: Trunk analysis
I would walk up to each vine and analyze the state of the trunk. Do you have one or two good trunks worth keeping? Is is relatively straight and disease free all the way to the fruiting wire? If it is less than perfect, then is it good enough for one year? Is there some wood that you can contort into a suitable trunk for a year? Do you have too many trunks?
- Trunk is in good shape for the long term : Cut off all suckers emanating from the trunk that are more than a foot from the fruiting wire (suckers below the head area). We won't need them. Suckers close to the fruiting wire might still be useful, so keep them around for now. Proceed to step 2.
- Too many trunks, none all that great: Pick one or two sections of vine that you can turn into a decent trunk for one year. Prune away all competing trunks at the ground and remove the tangled mess. Proceed to the bullet below.
- Trunk isn't so great, but you can make something work for a year: Straighten the trunk as best you can. Pick one sucker close to the ground and prune it to 2 buds. Use it to grow a new trunk this year. Prune off the rest of the suckers below the head (like in the first bullet) and proceed to step 2. Keep suckers/canes close to the head in case we need them yet
- Trunkwise, this vine is a total disaster: Find a sucker that would be good place to start growing a new trunk and prune it to that pont. You can prune 2 suckers this way if you want double trunks. If the vine is fairly weak looking, cut off everything else at the ground and move on to the next vine. If the vine is a healthy vigorous mess, then.... umm... take a picture and get back to us (this merits a deeper discussion)
Step 2: Cordon analysis
If you get this far, then you have some kind of usable trunk that runs from the ground to the fruiting wire. Next, decide whether you have some kind of usable cordon for a spur pruned system. This will look like a good run of old wood running down the fruiting wire with smooth canes shooting out from it all over the place. You might not have a good cordon, or you might have what looks to be a good cordon, but you only see old wood emanating from it for the first 8 inches or so. Note that you might have vine that has a good cordon running in one direction, and nothing useable in the other. In that case, prune each half independently of the other.
- Good cordon with lots of canes shooting out from within 6 inches of it : Prune every node of the cordon down to a single spur consisting of 2-4 buds. That node probably had multiple canes shooting out from it. Remove all but one to create the spur.
- No good cordon : Pick 2 healthy canes emanating from the head area that you can turn into new cordons this year. Cut off everything else. Lay those canes down on the wire, one running in each direction.
Step 3: Bud count
When you are done, you want to retain a certain number of buds on the vine. The exact number depends on the variety, but as a general guideline, you should retain around 5 buds per foot of cordon, with a total bud count in the range of 30-60. Since the vines are a tangled mess, you will probably start on the high side and need to work down.
Tips:
- Assuming you have a good trunk, then you pretty much know that you are going to keep short spurs or a couple of canes emanating from the head. If the vine is a gnarly mess, you can start whacking at it to get a better picture. Keep the two healthiest canes coming out of the head. You might use them, you might not. Cut all other canes down to 5 buds to remove the mess, then re-assess where the vine is at.
- It is wise to keep two canes from the head until you know you don't need them. When you are done pruning spurs, you might think "this cordon kind of sucks now that I look at it". If you kept those canes handy, you can remove the cordon and lay the canes down to make a new one.
- You don't want vines overlapping each other on the trellis. While obeying the proper bud count, chop of cordons that overlap.
Good luck
H
