View Full Version : How to trim forsythia?

agrostis palustris
08-07-2002, 02:20 AM
How do you trim forsythia? I just did a pruning job for a customer which included the severe pruning of a couple rhodi's as well as trimming back some forsythia. The customer requested that I get the top of the forsythia... however that is pretty hard to do. There are 3 of them which are in question. They are each about 8 feet tall. 2 of them combined are 30 feet across and probably 50 feet in length. The other 1 isnt as bad. I have access to a stihl extended shaft pole trimmer, but that won't do me much good. I could also get a trimmer attachment for my HT-75, but that would be heavy as all heck. Not ready to spring the $120,000 for the new Hi-Ranger yet... so that is also out of the question.

08-07-2002, 06:43 AM
At this point in the season I would sheer the Forsythia(use a ladder, or bring the tops down some) Extended sheers at 8' should not be problem. Late Winter I would cut them back. How far back did you prune your Rhododendrons???? i have never had much luck pruning this plant drastically.

08-07-2002, 08:35 AM
Any pruning now of the forsythia will reduce the flowers next spring. The best time to prune forsythia is after it blooms, much like lilacs.

If you must prune now, head the branches back selectively. If budget doesn't allow for hand work you can sheer them, however, this will certaily destroy the natural branching characteristic and will most likely remove more flower buds than if you selectively hand prune that which you must prune now.

The natural branching characteristic of the plant is whispy and flowing. Many people don't like the unkept look of the forsythia - it's a plant better suited to out of the way locations where they have room to grow and do their thing. Not a great plant in a high maintenance bed.

I have seen this plant in places where it has been continously shorn (sheered) and it blooms full of yellow each year. Go figure... I guess it depends on the look you want.

Specifically answering your question of how to prune the monster... I would at this time remove the three D's - Dead, diseased and damaged wood. I suspect with a plant the size you describe you'll have some deadwood in it. Sounds like you may be crawling on your belly to get to the base of the plant where you'll want to make your pruning cuts for removal. After you remove the 3 D's, do some light thinning of those branches that are crossing or rubbing others. Lastly, very light heading back of some of the "out of control" branches. You can use pole pruners, loper or hand pruners. Try to make each cut back to a lateral branch or bud. May be tough to do with the pole pruners.

Next spring after the bloom is finished before the plant leafs out do more thinning and heading back. Remove no more than 1/4 of the plant. You can rejuvinate the forsythia over three to four years by removing 1/4 of the oldest, woodiest canes/branches each year. The reduced shoot to root ratio will encourage new, young, vigerous growth. You can than work to keep the plant headed back to a more appropriate size if need be. But it will take time since you can do all the rejuvinating at once.

08-07-2002, 09:14 AM
Yeah, what HE said. This really couldn't have been explained better. Very well put, and informative. (Well, all except for the last sentence, but we know you meant to say CAN'T instead of can. {been there - don't you just hate it when that happens}. Anyway, geat thread, and even BETTER post. Good work, LawnLad!:)

08-07-2002, 08:25 PM
I think he was asking how to reach the tops, as opposed to how to trim forsythia in particular. If the shrubs are together, and pretty dense, I lay an extension ladder on top of the bushes. Then I climb on the ladder, crawling along, cutting. The forsythia have to be pretty think to hold the ladder, but we have done this many times with success.

agrostis palustris
08-07-2002, 09:02 PM
Thanx Ken. Your answer was more along the lines I was looking for. What is the biggest ladder you have ever placed on top of thick forsythia? I was able to lean my weight into it the other day and it supported me no problem.

08-07-2002, 10:25 PM
You can always try to drag a step ladder underneath, thin a spot, and pop up through it.
I would not worry that much about blooms as they bloom all over the younger branches. They will be covered in blooms next spring - except there will be less shrub to cover.

08-08-2002, 12:41 AM
It should be trimmed in the spring, shortly after blossom. I thin one-third out (taking the oldest wood) and then shape it. The blooms next spring will occur on the wood and buds developed on this years growth. The rule of thumb from my woody plants instructor was, "If it blooms before Memorial Day prune in the spring, if it blooms after Memorial Day prune in the fall."

Hope this helps.

08-08-2002, 01:59 PM
I usually take my 30' extension ladder and open it to the size of the bush. the longer you can open it, the more your weight will be distributed.

08-09-2002, 07:30 PM
ooops... I think you're right - you did ask on how to get on top of the forsythia. I guess I didn't read it close enough on first reading. Well, hopefully the info helped someone else.

I too would lean a ladder into the bushes... don't have to do it very often, but it works.

08-11-2002, 10:11 PM
Doug..thanks for the ellaboration, even if off the question.

Another bit of advice that will be printed and saved..


08-15-2002, 09:59 PM
" How to trim Forsythia " .. ????

Well around here we use a back hoe.... Yank em out and throw em into the compost heap..... LOL..... Most people hate them around here.. but we are so close together, if you let one grow without trimming for more than two years you cant get into your back yard , cause it's a bush.... Seriously...LOL...... I have a three legged orchard ladder that allows you to get in really close and into the bush. works on lots of apps,, should look into them.. much safer to set up on uneven ground , which is all turf .....

08-19-2002, 09:25 PM
I guess I've been doing it all wrong! Very informative LawnLad, I'm sure this is the "proper" way to prune. I've got an account where I shape them annually, just after blomming as you mentioned. Only thing is, I use my hedge shears and prune them like a shrub. The client has commented at how thick they bloom each year.:confused:

I have another account where there is a 150' Hemlock hedgerow similar to what Agrostis describes, I put my leaf box on my dump and drive it alongside the hedge for a mobile work platform. It goes much faster with a second guy who remains as driver/cleanup man. Then just fluff up your tire tracks with a leaf rake and no one knows the difference!

08-24-2002, 12:19 AM
Ever hear of Dura-stilts? I have used them a number of times on high, long shrubs and the take alot of the work out of getting up and down the ladder to move it around.

If you've never seen or heard of them, they are exactly what they sound like.... stilts. Mostly used for sheet rocking I think. They are pretty high tech, having joints and suspension(sort of) in the ankle area. They strap to your calf and foot area, and adjustable to give up to something like 2 to 3ft of height increase. Here's a pic... http://www.durastilt.com/
Takes a little getting used to but once your comfortable on them watch out... you'll be moving around like your on stilts. :) Just look out for bees nests while on them w/ hedge trimmers in hand... I had the most unpleasant experience of trying to run from wasps while in them. Didnt work and good thing the hedge trimmers landed next to me and not underneath me.