NEWS for North Dakotans
Agriculture Communication, North Dakota
State University
7 Morrill Hall, Fargo, ND 58105-5665
July 30, 1998
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Can you tell me what causes this condition on my hoya? Also, my cactus is in full bloom and is quite beautiful. (Detroit Lakes, Minn.)
A: Definitely salt or fertilizer burn, possibly combined with poor drainage. Congrats on the blooming of your cactus. It's rewarding to see it in flower anytime.
Q: I am enclosing a leaf from a mountain ash. Can you please tell me what is wrong with it? Also, when should a person transplant columbines? (Walcott, N.D.)
A: It appears that the mountain ash is suffering from poor drainage, compacted soil or too much water.
Columbines transplant easily just about anytime. I have popped them out of the ground to move them around when needed. I generally do it in the early evening and water in. Less stress on the plant at that time.
Q: I have a columbine that is about 4 years old and has always had mauve flowers. This year half of the blossoms are mauve and half are white. What causes this? (Langdon, N.D.)
A: Sometimes when they self-seed, genetic crossing will give a new generation of mixed colors. However, don't fret. I have never seen a columbine I didn't like.
Q: I have phlox plants that just don't bloom. They are quite thick and I plan to thin them this fall. Would this help? Also, when is the best time to transplant lilies and mums? (LaMoure, N.D.)
A: Definitely thinning would help the phlox bloom. Wait until several frosts have hit them.
I have transplanted lilies any time the spirit has moved me when the soil isn't frozen or the mosquitos too thick. Mums can be moved anytime as well. Many people will have a "mum garden" where they grow them during the early summer, then move them where they want for show around the time they come into bloom. Just make sure the site is in full sun.
Q: Would you please tell me what is wrong with my maple tree? Do fern leaf peonies take the same care as regular peonies? Are Japanese tree lilacs slow growers, and are they OK to plant in this area? Also, do you need to have two mock oranges to get them to flower? (Winner, S.D.)
A: Your maple looks as if it is suffering from too much salt (fertilizer burn or naturally high soil salt content) or is planted too deep. Try to improve the drainage around the plant site if possible, even if it means resetting your tree.
Basically, the peonies all require the same care. Japanese tree lilacs are among the most trouble-free plants to use in our prairie landscapes. They are not slow growers and have an attractive cherry-like bark. Get one!
No, you do not need two mock orange shrubs. Lack of flowering could be due to not enough direct sun, too much nitrogen fertilization or improper pruning. It could be, too, that you really don't have a mock orange!
Q: Can you identify this plant that I have enclosed? It seems to be a very prolific plant that is growing all over the yard. I think the birds are spreading it when they harvest the berries. (Audubon, Minn.)
A: The plant was in rough shape, but we were able to get it identified. It appears to be Scarlet Elder, or Sambucus pubens. This is a good plant for naturalizing, to attract birds (obviously) and for making jellies. It will grow 12 to 25 feet in height with an equal spread. It is not a noxious weed.
Q: Enclosed is a leaf from a 40- to 50-year-old cottonwood tree, and it seems that the leaves are turning brown and falling off. The green leaves have a pod on them that is filled with some kind of bugs. (Seneca, S.D.)
A: The leaf sample you sent had leaf petiole gall aphid growth. This is a common occurence on poplar or cottonwood trees and, other than disfigurement for the growing season, causes no serious damage to the tree.
The other spots on the leaves are one or several leaf spot fungi that beset this poor species.
To control the gall aphid, spray the tree next spring as the leaves unfold with a systemic insecticide like Orthene. Controlling leaf spot diseases is almost a lost cause, but you may want to try Bordeaux mixture right after leaf-out.
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Source: Ron Smith (701) 231-8161
Editor: Barry Brissman (701) 231-7866