Forsythia

April 29, 2017

We have had a forsythia bush for the last 7 years.  It has grown wildly and we have pruned it back several times, always being careful to prune right after it is finished blooming.  However, it has never bloomed out fully down each branch like many in our Sherwood neighborhood do, instead blooming only at the ends of the branches. It gets plenty of sunlight (6-8 hours daily), and we have kept it watered throughout each summer.  Do you have any idea why it won’t bloom out fully?  We are about ready to dig it up and plant a different kind of bush.

My guess is you are pruning your forsythia by simply heading it back from the top on all of the branches and not removing the older canes at the soil line.  Forsythia doesn't have a main trunk, but multiple canes. To keep them blooming from the top down you need to remove the older, woodier canes at the soil line.  This will allow new vigorous canes to emerge from the ground up and these should have flowers all the way down the stem.  I would suggest removing a third of the canes every year.  It is best to prune as soon after flowering as possible, but no later than mid-June.

(August 2012)

We have a very unruly forsythia bush that is about 30 years old and anchors the planting at the end of our front porch. Is it okay to prune it now or in the fall when it drops its leaves? It really needs a good shaping but we want to have flowers next spring also.

Flower buds are set on your forsythia for next spring. If you prune now, you will lose flowers. The best time to prune is immediately after bloom next spring. Take out 1/3 – ½ of the older, woodier canes right at the soil line. This should rejuvenate the plant and reduce the size.

(March 2012)

We have three large forsythia bushes that bloomed spectacularly up until about 5 years ago. Two of them are in full sun and one is at the north edge of light woods. The oldest shrub is over 20 years old and we cut it way back about 3 years ago because it failed to bloom except for a few blossoms on the tips of the branches. It's never really bloomed well since although it regained its original size in 2 years! These shrubs have some kind of knotty gall-type growths on the branches. Many of our neighbors have absolute thickets of well-blooming forsythia so I can't believe it's because we haven't pruned our shrubs. We cut the oldest bush down to the ground this week (it had grown up around a martin house) and hope it will come back and bloom for us. Can you give me any advice on what may be wrong?

I think you have two problems-one is that you aren’t pruning correctly, and two, I think you have a disease known as Phomopsis galls. Gall symptoms on forsythia are brown clusters which encircle the stem which vary in size from ¼ to more than an inch in diameter. The galls are often clustered along the stem, eventually causing twig dieback. Control consists of pruning out the galls and disposing of them. Chemicals are mostly ineffective. Severely infected plants should be cut to the ground. Remember that forsythia is a cane producing plant—it doesn’t have a dominant trunk. For now prune out all branches that have galls, at the soil line. In future years if they don’t have galls, remove 1/3 of the older, woodier canes at the soil line every year after bloom. This rejuvenates the plants and encourages new growth which will have more blooms. I do think the older plant that has been cut down, should start to grow again, and hopefully will be spectacular next spring, provided no new galls occur. The more sunlight, the better they bloom too. If the only pruning that is done is cutting the plant at the top to make a large ball or box, all you are doing is leaving older canes which will bear flowers only on the tips where the new growth occurs.

(September 2010)

Our forsythia bush seems to be dying. It has developed a lot of dead branches and leaves this summer probably due to the hot weather. I want to cut it back severely to hopefully give it a fresh start, but don't know when to do it. Do I do it this fall when it's going dormant, or spring before it starts to leaf out? Also, we usually get less than twenty blooms on it in the spring. Will cutting it back help?

Many plants have suffered this summer, but forsythia is usually pretty tough. I would just water for now, and then assess the health of the plant next spring. Forsythia have their flower buds set now for next year’s blooms, so severe pruning will remove even the 20 or so blooms you get. Does the plant have full sun? Is the soil well drained? Forsythia needs at least 6-8 hours of sun to bloom. If it still looks bad next spring, you have a few options. One is cut it completely to the ground and let new sprouts come up and start over. A less drastic approach is to remove one third of the oldest canes at the soil line. Water and fertilize and see what happens.

(April 2010)

Could you please help me determine why my forsythia bushes which are very large, will only bloom a couple or three blooms each year, while my neighbors are solid yellow with blooms. The bushes are several years old and every year I think next year will be better, but it isn't.

If they get plenty of sunlight then the problem is probably that they are older bushes that you are not pruning. Forsythia sets flower buds in late summer on the growth it puts on during that years growing season. If the bush is old, it doesn't do a lot of new growing since a plant can only support a finite amount of growth. To encourage new growth you need to prune out one third to one half of the older canes every year following flowering. When pruning forsythia, we don't want to shape them into balls or boxes, since we want a living fountain for a plant. To achieve new growth and retain the structure, thin out older woody canes at the soil line. This will rejuvenate the plant, sending up fast growing new canes which should be loaded with blooms next spring--again, as long as they get 6-8 hours of sunlight a day.

(March 2005)

I have three forsythia bushes and only one blooms. I treat them all the same as far as pruning and fertilizing. I have a six foot privacy fence around my backyard and the bushes are planted in the corners. The two that do not bloom are in the southwest and northwest corners. The southeastern corner blooms. What do I need to do to make them all bloom?

Forsythia blooms best in full sun. Is there a difference in the amount of light they receive? It also blooms on one year old wood. Prune out up to one third of the old canes annually in the spring after bloom. If the two shrubs that are not blooming are being shaded, your only option would be to move them to a sunnier location or limb up some trees. They need at least six hours of sunlight a day for flowering.

(April 2010)

Could you please help me determine why my forsythia bushes which are very large, will only bloom a couple or three blooms each year, while my neighbors are solid yellow with blooms. The bushes are several years old and every year I think next year will be better, but it isn't.

If they get plenty of sunlight then the problem is probably that they are older bushes that you are not pruning. Forsythia sets flower buds in late summer on the growth it puts on during that years growing season. If the bush is old, it doesn't do a lot of new growing since a plant can only support a finite amount of growth. To encourage new growth you need to prune out one third to one half of the older canes every year following flowering. When pruning forsythia, we don't want to shape them into balls or boxes, since we want a living fountain for a plant. To achieve new growth and retain the structure, thin out older woody canes at the soil line. This will rejuvenate the plant, sending up fast growing new canes which should be loaded with blooms next spring--again, as long as they get 6-8 hours of sunlight a day.

(April 2006)

I have three Lynwood Gold Forsythia that are two years old and have never been pruned. They are growing in full sun and they will not bloom. Is there any reason why they aren’t blooming, and anything I can to get flowers?

Are they putting on new growth? Forsythia sets its flower buds in late summer/early fall on the growth it has put on during that growing season. If for some reason the plants aren't putting on any new growth during the summer, there would be few flowers. People who prune them into specific shapes-- balls or boxes, leaving primarily the older growth, see very few flowers the next spring. Try taking out one third of the canes at the soil line after they fully leaf out. This should rejuvenate them, causing new canes, where there should be ample flowers next year. If there is something impeding the roots from growing, you often won't see much top growth, and then reduced flowering. I am surprised you have no flowers, since even poorly pruned older plants usually have a few straggling blooms on the tips, as long as they are growing in full sun.

(March 2005)

Can I cut back the forsythia after it blooms? And isn't it time to cut back the Rose of Sharon bushes, crepe myrtles and butterfly bushes?

Forsythia should be pruned after bloom. Remove one third of the old canes down at the soil line to encourage new growth. There is still time to prune Rose-of-Sharon, crape myrtle and butterfly bush, as all of these plants bloom on the current season growth. Try to do it soon since new growth is beginning.

All links to external sites open in a new window. You may return to the University of Arkansas System Division of Agriculture web site by closing this window when you are finished. We do not guarantee the accuracy of the information, or the accessibility for people with disabilities listed at any external site.

Links to commercial sites are provided for information and convenience only. Inclusion of sites does not imply University of Arkansas System Division of Agriculture's approval of their product or service to the exclusion of others that may be similar, nor does it guarantee or warrant the standard of the products or service offered.

The mention of any commercial product in this web site does not imply its endorsement by the University of Arkansas System Division of Agriculture over other products not named, nor does the omission imply that they are not satisfactory.