September is an excellent time to prune your American wisteria (frutescens or macrostachys) (if you have had reliable bloom each year for several years, it is probably an American wisteria. Or if you notice that it blooms on "new wood" or new growth, it is American, not Asian). This is one of the exceptions to the “don’t prune in the fall” rule. Pruning wisteria now will allow for better bloom next year, plus it will keep this rampant grower in check. My wisteria did not bloom much this spring, then gave off blooms in fits as starts (and small amounts) this summer. So prune it we did. Or rather, I armed my 13 year old with pruning shears, saws and instructions…and he did a great job! (thirteen year old boys are great on “seek and destroy” missions!).
The instructions to prune a wisteria are to cut back each vine from tip to 3 feet or more back into the mass. Cut off any broken, damaged or diseased vines too (though not much seems to bother this plant). If your wisteria is near a building, cut off any vine that contacts the building. Wisteria vines will worm their way under soffits, shingles, around decks, fences and downspouts…and will tear them off over time! The best place to put a wisteria is away from the house. If your wisteria, like mine, was starting to reach into the neighbors tree, cut that off too. Wisteria will form a very thick, treelike and hard-to-cut trunk over time and needs strong support.
As you can see by my “after” photo above, I planted my wisteria to take over the play yard in our back yard. By the time it is engulfed, my son (and my nephews and niece) will have outgrown the swings. Before pruning, we could not see the yellow side nor one of the swings, so trimming back gave us another year of use of the swing set.
One fun thing I did with the trimmings is make several wreathes and the swag surrounding my fireplace (in the photo). I am drying other vines and flowers (and I actually ordered some cool dried flowers on line) to make up the wreathes and swag. I will keep a wreathe, give some as gifts and will have the swag ready for Thanksgiving (when I host more people that ever before!). I hate to waste stuff as much as I love to collect botanical materials.
(One historical note: the wisteria is named after Caspar Wistar and should be called "wistaria", but for a typographical error!)