Questions on: Forsythia
Ron Smith, Horticulturist, NDSU Extension Service
Q: Last year one of my miniature barberry bushes suffered about 90 percent winterkill and another about 60 percent. We replaced one and are waiting on the other to see if it turns out looking better than it does right now. Can I prune away the dead limbs? Will it eventually fill in with new limbs? Should I have mounded dirt or mulch at the base of the plants or covered them in leaves last fall to prevent winterkill? I just planted a dwarf fiesta forsythia. Since Bismarck is technically Zone 3 and the barberries and the forsythia have northern exposure, should I somehow cover the base this fall also to prevent winterkill? (Bismarck, N.D.)
A: Barberry bushes seldom do well in our region, so I would encourage you to opt for something else. They are the alternate host for stem rust on our cereal crops. Since the forsythia is being established this early, I see no need for providing cover. If it makes you feel better to do so, go ahead. I never have known any forsythia that died because of winter problems.
Q. Should I cut back the dead foliage on the lamb's ears. And also, how should I prune my forsythia? (e-mail)
A. Yes, go ahead and remove the foliage on the lamb's ears, being careful to not damage the newly emerging foliage for 1999.
Pruning forsythia requires no special skills. Simply cut back the oldest, heaviest stems as close to the ground as possible. They flower on last season's growth. I have tried to kill one that has overgrown my property by cutting it back severelyand still it grows and flowers! If yours has flowered already, then cut those canes back. This is one of the best plants for abuse tolerance, so don't worry about making mistakes. The plant will recover and forgive you in a year or two.
Q: My forsythia just blossoms on the short bottom branches. It grows about 4 feet a year. The upper branches either leaf out or are just dry.
A: The forysthia is showing marginal hardiness for your area. The flower buds above the snowline are killed, while those below it survive. The fact that the vegetative parttree leavesget killed off indicates to me the need to replace it with a hardier cultivar. Try `Meadowlark,' an introduction from NDSU. It is the hardiest on the market.
Q. Received a Meadowlark forsythia many years ago. This year it's beautiful, all yellow with bloomthe first year it ever bloomed, so this proves it's not really a plant from this part of North Dakota. (Hannaford, N.D.)
A. Any plant material released by NDSU horticulturists undergoes 10 years of evaluation of seven different sites around the state. If they don't measure up, they never make it.
My only guess is that you must have received a mislabeled specimen or the conditions were so bad at your particular planting site that the flower buds were injured.
The plant has been a great success industry-wide in the northern U.S. and Canada.
Q. Once again I look to you for answers. I read that corn gluten meal can be used for crabgrass. Where might I be able to find an outlet for it in North Dakota?
Also, what are forsythias? I have looked in all my seed catalogs and can't find them. (Bismarck, N.D.)
A. Corn gluten meal is an organic means of controlling weeds. Timing of it is critical to be effective. As far as I know it is not available from any retail outlets at this time, but can be purchased through garden catalogs like "Gardens Alive," phone 812-537-8650.
Forsythias are woody plants that produce yellow flowers in the early spring. These are commonly available from nurseries and garden centers.
Q: Searching through the net about forsythia plants, I came up on your web page. I know you are in North Dakota where it gets pretty darn cold, but it also gets a little cold here in North Carolina. My question is, do I trim my forsythia the same here as you would in North Dakota? I only have one that I use to hide the gas line going to my fireplace and it has just about taken over the side of my home. It is about 6 feet in diameter and almost 7 feet tall. I don't want to kill it, but just how far back can I trim and when? ((E-mail reference, North Carolina)
A: Your damp cold can be almost as discomforting as our lower temperatures. I used to live in the South -- Georgia, Texas, and Arizona -- so I know a little about what goes on there. First thing, you probably don't have to worry about killing a forsythia that is as established as yours is. Years ago, I tried killing one by severe pruning and failed. I finally had to bite the bullet and grub the thing out of the ground, which was a lot of work. You can prune your plant at this time of year, and probably bring some of the prunings inside for a centerpiece, as they will flower easily once inside in a vase of water. I suggest cutting about one-third of it back as close to the ground as possible whenever the spirit moves and the weather allows. If you can, reach in with long-handled lopping shears and cut the largest canes at the base, then cut the top back to a bud to the size you want.
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