Have grown forsythia bushes; when do you prune or trim and how much? There are old canes in the bushes.?

If the bush is in an area with plenty of room to grow, ya really don't need to trim it. Can prune out the old canes after it is done flowering. I leave mine alone and it looks beautiful all summer long. It has suckers coming up around it. I let some grow for one season and then transplant them elsewhere in the yard. The young plants grow just fine and soon I'll have a many pretty yellow bushes.

Have grown forsythia bushes; when do you prune or trim and how much? There are old canes in the bushes.?
I would prune out the old canes, forsythias bushes are very tough and most shrubs with canes benefit from removal of the very old canes over the years. I was unsure apart from this but have a good book on pruning from the British Royal Horticultural Society so I quote the following passage from their book:





'Annual pruning immediately after flowering in early spring is necessary, especially for F.suspensa when grown against a wall or fence for which its lax habit makes it particularly suitable. Forsythia x intermedia 'Spectabilis' and other strong-growing types have a very vigorous growth reaction to severe pruning, and flower production may suffer in consequence, although they make good hedges, flowering freely if clipped to shape once or twice during the growing season.'





Another book says prune only to remove older branches, so it sound like you should just give regular light prunes, and chop out your old canes. Hope this helps.
Reply:When I did shrubs commercially, I would schedule forsythia for when the flower pettals were falling off.





We say they bloom on old wood, because they will set the flower buds on the wood that grows in the summer and they hold till spring. Most early bloombing plants are like this.





Those that flower one "new wood" set the flowers on the new shoot and bloom the same year.





To get around this, but maintain a nice looking plant, I would thin out 1/3-1/4 of the largest stems as low as I could cut. This "renewal" prune makes it so that there is allways a 3-4 year old plant above gorund, so that you have young vigorouse canes bearing flowers and leaves. The plant does not have to work supporting lon geavey woody stems that get diseases.
Reply:i heared that if your put bleach on forsythia bushes they grow nice a green
Reply:We found a forsythia in our new home when we moved -- it had been neglected and did not have many blooms. We pruned it back quite a bit and this year it has the most blooms ever. Evidently regular pruning will help to keep the blooms coming - I would not recommend just letting it go. The canes that we pruned had gotten real long and were drooping back towards the ground -- we pruned it to about a 4 foot bush - maybe 4 1/2 foot.
Reply:My husband always says when in June that's when you prune. Ours grow at least 5 feet tall, Usually after they stop flowering,We prune them also. I have also taken some of the canes, that I remove and put them in water and root, to make more plants.
Reply:Do not prune heavily or will not bloom the following year.


You can cut out the dead canes or older ones but unless you do it in the fall in dormant state it will shock it too much and you may wait years to see blooms again. Still do not cut all the canes, if you must prune in the fall, so some will be left for blooming come spring.