Forsythia

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.

April 2012

When to prune.

It has been a gorgeous, albeit early spring this year in Arkansas. Many early spring blooming plants are finished blooming and beginning to put on new growth. Now is the time to prune them if needed. Remember that before you grab your pruning shears, you need to answer three questions, why am I pruning, when should I prune and how should the plant be pruned. Some plants require annual pruning, while others may never need to be pruned. Plants that bloom in the spring should be pruned as soon after flowering as possible to allow plenty of recovery time before they start setting flower buds in the late summer/early fall. You have until mid June to get it done, but the sooner, the better in my opinion. Forsythia is a cane producing plant. What that means, is that it doesn’t have a dominant trunk, but multiple trunks or canes. To prune it properly you should remove up to 1/3 of the older canes right at the soil line every year after bloom. This will encourage new vigorous canes to grow, giving you the living fountain look and plenty of flowers next spring. If your azaleas are too large and need to be pruned, do so when they finish flowering. Azaleas do have a dominant trunk, so we do selective thinning when pruning them. Many folks make the pruning job easier and use electric hedge trimmers and create all these meatballs in the landscape. When that is done, the end results aren’t as pleasing. When pruned at the exact point on each plant, all new growth will be on the edges, as will all the flowers. If you can, selectively thin at staggering heights throughout the bushes. This will give you a more full, natural look and more flowers next spring.

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.

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