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Published August 14, 2009, 12:00 AM

Prune out unwanted bush peonies this fall

Q: I have a beautiful peony tree. However, the past few years I have found that a regular bush peony that I did not plant is growing out of the same root area as my tree.

By: Don Kinzler, INFORUM

Q: I have a beautiful peony tree. However, the past few years I have found that a regular bush peony that I did not plant is growing out of the same root area as my tree. The same thing happened for the first time this year with another tree peony. How do I get rid of these bush peonies? I am afraid to dig them up because I do not want to hurt the roots of the tree peony. (e-mail reference)

A: About the only thing I can suggest is to prune out these vagabonds carefully after the plants go dormant this fall. You will have to follow the stem right down to the base and dig out any root material you can. For the time being, you can cut the offending foliage back.


Q: I bought two hibiscus plants three weeks ago and replanted them in bigger pots. They were doing OK until about a week later. I had my husband put holes in the bottom of the pots for drainage because the leaves started to wilt. I added plant food and they get sun at least four hours a day. The leaves are worse now, but they still have buds. What should I do? (e-mail reference)

A: Just be patient. Give the plants normal care and hope they recover. Root rot might have started before you had holes drilled into the containers. If the plants have good vigor, they might be able to overcome this; otherwise there is nothing else you can do except wait.


Q: I have a beautiful weeping birch tree. We recently bought a new house and I am interested in trying to start a new tree from a seed. Our tree is full of green pods right now. Any advice? (Williston, N.D.)

A: You can start birch trees from seed by planting in the fall or late in the winter where they are allowed to freeze for a couple months before germinating.

Softwood cutting will root fairly well if they are treated with a rooting chemical and then put under a mist. Lastly, low-growing limbs can be layered successfully, but be sure the limb used is from a young tree. Birches are great at natural hybridization. If there are other birch trees within the vicinity of your tree, you could get some varying characteristics from your seedling collection. When sowing the seed this fall, be sure you don’t bury them too deeply. Cover the seeds with about a quarter-inch to no more than half-inch of soil. If you want to be more experimental, take some of the seed and stratify it in moist sand in the crisper of your icebox for about three months. Then plant the seeds using pasteurized soil in containers to germinate the seeds.


Q: I have a brief question for you about a weeping birch tree I planted last year. I purchased my home last year and had to start with a bare yard. I went to a great nursery and fell in love (at first sight) with my birch. I dug the holes for all the trees and the guy from the nursery helped me plant them. I would say it was about 20 feet tall when I bought it. I also planted it with the nursery-recommended fish fertilizer and root rub.

The tree was great until the new neighbors next door put in a new lawn and were overwatering. I was on vacation when this happened, so when I returned home, my poor birch was yellowing.

I pulled the mulch and stopped the overwatering from happening. I also gave it a little root stimulator.

Now the poor tree looks OK, but the leaves are small and there are numerous pods all over the tree. I was thinking that the pods are making the tree look bare. There also are not many leaves toward the top of the tree. Any suggestions? (Thornton, Colo.)

A: You probably can get some decent advice from the nursery where you made the purchase, but it sounds like the tree is going through the last stage to perpetuate its survival. The tree could be infested with bronze birch borer or root rot due to the overwatering.

I would encourage you to get this tree removed and replaced with another one. Before you do that, find out what is killing it and take the necessary corrective action to keep it from happening again. When my wife and I moved to our home in Fargo in the mid-80s, we planted a weeping birch. Everyone told me the tree wouldn’t last more than seven years. That was more than 24 years ago and it is now the striking beauty of the neighborhood.

Instead of mulch, I would suggest that you surround the base of the tree with a creeping ground cover, such as strawberry plants. The strawberries we planted are now long gone, but we have herbaceous perennials growing under the majestic canopy now. The tree and plants seem to get along just fine. In a nutshell, this tree species is worth reinvesting in for the beauty it will bring you as it ages. We all should look this good as we get older.


Q: We were looking to plant some miniature lilacs for privacy next to a chain-link fence. Currently, we are painting the fence. If we need to paint the fence again, could the lilacs be trimmed to get closer to the fence? Could we kill the bush by doing that? I need to know roughly how far away to plant the lilacs from the fence for future maintenance. (e-mail reference)

A: You can plant them 4-plus feet away from the fence if they are miniature lilacs. When painting as you describe, I’ve always tied them together with a strip of cloth and didn’t harm the plants. The miniatures are not that wide spreading, so it should not be a matter of great concern.


Q: I am looking to plant some vines to cover up an unsightly chain-link fence.

There is 90 feet of fence that is 4 feet tall and gets full sun. I would like something that grows quickly, is minimum maintenance and pretty (flowering in the summer or colorful in the fall). Do you have any recommendations? What is the best way to do the planting? It currently is lawn. Should I plant the vines in the lawn and maintain the lawn around it, or should I remove the grass and put down a mulch after I plant? (Chanhassen, Minn.)

A: It is funny how everybody wants a plant to have so many qualities, such as fast growth, nice flowers, low maintenance and nice fall color. I don’t know of a vine that can meet all of those qualities. Sorry! However, I do have a few suggestions for you to consider. Thanks for letting me know where you live.

Bittersweet is grown primarily for its fruits, which are used for winter bouquets. Bittersweet requires good light and a support to produce an abundant crop of fruit. Since each bittersweet plant usually is of a single sex, several plants should be planted in an area to make sure you get fruiting. Bittersweet is adapted to a wide range of soils. The height of some of these vines is determined by the height of their support. Some vines will spread on the ground and are useful as a ground cover. Bittersweet vines climb by twining. American Bittersweet is a native species that produces the most desirable bright orange fruits for fall arrangements.

Boston Ivy often takes a couple of years to become established, but then grows vigorously. It climbs by tendrils that often have disklike tips that will adhere to wood or masonry surfaces. Its leaves are three-lobed and dark green, but turn a bright red in the fall. Dieback to the ground is common with young plants and occasionally occurs on older plants.

Englemann ivy climbs with adhesive disks at the end of the tendrils. It has a compound leaf made up of five leaflets similar to the woodbine, but the leaflets are smaller. It takes on a bright red fall color.

Dropmore honeysuckle blooms from early in the growing season into the fall. The abundant, showy flowers are an attractive red-orange. Its foliage is a rich green. This vine climbs by twining and will grow 10 to 15 feet if support is provided.

Trumpet creeper climbs by aerial roots. Although not considered dependably hardy, it sometimes is seen in southern Minnesota. It grows best in a sunny location and in fertile soil. The large trumpet-shaped flowers are yellowish orange to scarlet and appear in July. This vine needs a sturdy support. Dieback is common after a severe winter.

Also, your vines will get a much better start along with better subsequent growth if you did not just plant them in the sod. Besides root competition, there potentially could be mower damage or monofilament injury.


Q: I’m having trouble with my cucumber plant. Whenever a cucumber begins to grow and it gets about 1 inch long, it starts turning yellow. After it is completely yellow, it shrivels up and dies. I don’t know why it is doing that. I water it twice a day and it is in complete sunlight all day.

A friend of mine told me that it may be some kind of disease, but I cannot match it up with anything. Can you please help me? I have attached a file with some pictures. (e-mail reference)

A: Your problem is that you have just one cucumber plant in a small pot struggling to make it on a patio. Cucumbers have two different flowers, male and female. Male flowers open first and always drop off. Female flowers form the cucumber and should not drop off.

If female flowers begin to drop, touch the inside of each male and female flower with a soft brush or cotton swab. This pollinates the flowers and helps them develop into fruit.

My guess is that your male pollinators are gone by the time the female flower arrives, so pollination is either nonexistent or minimal at best and results in loss of fruit.


Gardening or houseplant questions can be directed to: Hortiscope, Box 6050, NDSU Dept. 7670, Fargo, ND 58108-6050 or ronald.smith@ndsu.edu

Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations

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