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Thursday, October 20, 2016

Read This to Remove Confusion on Pruning Grapes

Q. I read your column about fruit and flowers only growing on 2 year old wood grapevines.  So now I am confused about how to prune my beautiful grape vines. Just what do I remove, or do I even need to remove any of the vines?

A. Yes, it can be confusing. Maybe you can think of grapes this way. The first year the plant pushes new growth. There is no fruit on first year growth (first year wood). This new growth must be fully grown and mature to support the fruit that will grow on it the following year (second year wood).
This is new growth of grape, a few months old. This growth will produce fruit the next year, second year wood.
The second year the plant again pushes new growth from its end or sides (first year growth). First year growth always comes from second year wood. While it is pushing this new growth, it is also pushing flowers and fruit to grow on the previous year's growth (second year wood). The vine is doing two things at the same time. It is always pushing new growth that does not support fruit (first year wood). At the same time it is pushing flowers and fruit from the previous year's growth (second year growth).
This is a grape flower cluster that will become a bunch of grapes in about five months. These grape flower clusters can only grow from stems or wood, that are growing in their second year.
Different grapes produce flowers and fruit in different locations along second year of growth. Some grapes produce flowers and fruit at the very base or bottom of the second year growth (second year wood). This fruit is mostly produced very close to the juncture of the first and second year growth. When pruning these kinds of grapes we only have to leave about 1/2 inch of the second year growth remaining. The rest is cut off. 
Immature bunches of table grapes developing along second year wood
Removing all of the second year growth except for one half inch results in a "spur" of second year wood. We say that these kinds of grapes should be "spur pruned". From these "spurs" we allow new growth but this new growth is always cut back again leaving only about 1/2 inch. From these "spurs", it is a continuous cycle of growth one year and cutting it back to 1/2 inch in late winter of the second year. Growth and cut back to a half inch, growth and cut back to a half inch, etc.
Grape vine pruned to spurs. The one year old wood is a nearly totally removed leaving behind only one or two buds. These spurs were left a little bit long because of fear from die back due to winter damage. Just before new growth begins, these spurs will be pruned even more leaving only one bud.
Other grapes do not produce flowers and fruit at the base of the second year wood. Instead, they produce flowers and fruit further away from the base at a distance of perhaps 10 or 12 inches from the base or more. When we prune these grapes, we must not cut back too much or we will remove all the fruit. When pruning grapes such as these we must leave very long spurs to accommodate for the flowers and fruit. We no longer call these "spurs" because they are too long. Extra long spurs are called "canes". Grapes that are pruned so that second year wood is 10, 12 or perhaps 18 inches long are "cane pruned".
Some grapes will fruit only further along the vine. If you spur prune these types of grapes you will remove all of the fruit. These types of grapes must be "cane pruned". A cane is simply a long spur that has 8 to 10 buds along its length rather than just the one or two on a spur.
When pruning grapes it is important to know where the fruit is produced along the second year wood. If the fruit is produced at the base of second year growth, it is "spur pruned". If the fruit is produced several inches away from the base, it must be "cane pruned".


  1. Thanks for that information! Are there any resources where I can find out if my particular variety is a spur-pruned or cane-pruned vine?

    1. There are two ways to figure it out. The first is to spur prune it one year. If you have no grapes then it should be cane pruned. The second is to cane prune it look at where grapes are produced. If some of the grape bunches are produced very close to the beginning of new growth then it can be spur pruned. The majority are spur pruned. Two that are traditionally cane pruned are Thompson Seedless and Black Monukka.