Spur pruning of grape delayed until just before new growth occurs. |
Whether you are growing wine grapes or
table grapes, it’s a good idea in our climate to delay the final pruning until
you are confident freezing, dry and windy weather has passed. The reason for
this is to minimize fruit loss because of cold, windy and dry late winter and
early spring weather. If you get eager and make your final pruning early, it’s
possible that cold, dry windy weather later might eliminate some or all the
fruit you intended to keep.
All grape bunches come from buds on last
year’s growth. In this way, fruit is produced much like fruit is produced by
peaches and nectarines. But this is where the similarity stops. Some grape
bunches (Zinfandel, Syrah and Muscat for instance) grow from buds very close to
where last year’s growth began. These types of grapes are “spur pruned”;
leaving less than an inch of growth remaining from last year.
Leave the canes a bit long and finish pruning when fruit clusters appear to “balance the load”. |
Other varieties of grapes (Thompson
seedless and Concord grapes for instance), their bunches grow from buds several
inches further out along last year’s growth. These types of grapes are “cane
pruned” because last year’s growth is left longer; 6 to 10 inches in length.
This allows the unproductive buds to grow without producing any fruit.
Grape bunches appearing in early May in Las Vegas. |
I delay pruning grapes in our cold
desert climate as late as I can. Sometimes even after new growth is well
underway. Delaying the pruning this long delays the chance of fruit loss because
of freezes and cold drying winds. In the Las Vegas Valley, final pruning may be
delayed until late February up until the first week in March. If you want to be
doubly sure and a bit lazy about it, delay final pruning until fruit bunches
show you where to prune. This might be as late as mid to late April or early May!
You can delay the final pruning of grapes until you actually see fruit clusters (bunches) appearing. Doing this can help balance the load of fruit and make larger berries in the clusters. |
This doesn’t mean you can’t do some
pruning earlier. Just be careful and not remove too much of last year’s growth.
It’s okay to leave last year’s growth about 12 inches long and cut it shorter than
this when you are confident new growth is about to begin or later.