You are here: Home Columns Hortiscope Hortiscope
Document Actions


Ron Smith answers reader's questions about the world of plants and gardening.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: We have flowering plums lining the driveway. Our only problem is the birds love the small fruit (which we don't eat). Unfortunately, the red fruit is staining the exposed aggregate. Is there a way to neutralize the tree so it will not produce fruit? I realize now that there are varieties that have been bred to be fruitless. If not, how do we make the fruit unappetizing to the birds? (e-mail reference)

A: There are sprays for controlling fruit set on trees, but they are not very dependable. I think the only solution to your problem is to have the trees removed and replant with something that is not going to be attractive to birds.

Q: I have a crab apple tree that produces an abundance of apples every year. I make jelly out of the apples. In July, the apples start falling off the trees. When is the best time to pick these apples, so I don't lose them all? (Long Island, N.Y.)

A: Check them now to see if they are ready or can be converted into a decent jelly. If so, pick them. Otherwise, you will have to wait until the fruit ripens enough to do so, which is variable from species to species.

Q: I have an autumn blaze maple that I planted last year. A patch of bark in the middle of the tree split and fell off. There also are a few other splits in the bark, but otherwise the tree looks fine. Should I do something or just leave it be? (e-mail reference)

A: Don't prune the tree for several years and wrap it every fall after a couple of good frosts. Remove the wrap each spring after the tree has leafed out. In the meantime, keep the splits clean of debris and insect gatherings.

Q: I am wondering about ninebark shrubs. What can you tell me about their hardiness in our dry sand of North Dakota? Also, what can you tell me about autumn purple ash trees? Do you think it is wise to plant anything ash because of disease problems? I am looking for something that grows fast and is pretty. (Tappen, N.D.)

A: The ninebark (Physocarpus opulifolius) is known for being a tough, adaptable plant to sandy and dry conditions, as well as alkaline or acid soils. Unfortunately, it looks tough (in my opinion), but can have its appearance improved somewhat by cutting it back to the ground every other year in late winter to encourage fresh flushes of growth. I would suggest staying away from any purple-colored deciduous trees in your location. They need more benign growing conditions than what your part of the state has. The rapid growth/pretty requirement is sometimes tough to match. Of course, beauty is in the eye of the beholder. To maintain beauty, care and maintenance must be carried out. If you are of such a mind, then the cutleaf weeping birch is one of the most beautiful trees I think a human being can lay eyes upon. Mine has outlived all predictions and still is going strong after 21 years. Other than that, one of the silver maple hybrids would do the job. Visit local nurseries to see what is being offered.

Q: My tree's leaves are turning yellow, then brown and dropping off the tree. We've had about 40 inches of rain this year in our area. I live in the north-central part of Oklahoma. (e-mail reference)

A: If that isn't a typo, then 40 inches of rain is what is killing your tree or at least causing premature defoliation. Don't count it dead yet. Wait to see if it leafs out for you next spring and hope that this biblical rainfall doesn't come back again!

Q: I'm looking for some help with oriental poppies. We planted a selection and got one good year out of them. This year, only one plant survived to bloom. In June, I planted an additional six plants that didn't even come up. Are oriental poppies difficult to grow in this area? (Fargo, N.D.)

A: They are not commonly seen in our area. The few that I have seen are beautiful and planted in a well-protected spot. Poppies are known for being difficult to transplant, so you are better off getting them into the ground through direct seeding and allowing nature to take its course.

Q: We were wondering if you have heard of or seen a yellow chokecherry here in North Dakota. I have a friend who has two on his farm. (e-mail reference)

A: While not common, there are yellow-fruited chokecherries. It is listed as Boughen's Yellow, so the name would be Prunus virginiana/Boughen's Yellow. The fruit can be used in the same manner as the common chokecherry fruit.

Q: We are having our foundation landscaping taken out. It consists of columnar arborvitaes at the corners of our L-shaped ranch and junipers along the foundation. The plantings are more than 50 years old and definitely showing their age. We would like to replace everything with similar plants, but wonder if it is too late in the year to do so, especially for junipers. If it is too late, what might we use instead? Also, we need to have a birch tree taken down. We tried hard to save it the last few years, but this year it died. It is somewhat the focal point of our perennial garden. What could we use that would provide us with a color contrast against flowers and greenery? The spot is on the east side of the house so gets lots of morning sun, but is shaded as the day goes on by a huge maple. (e-mail reference)

A: You can replant with junipers or whatever you want now because nurseries have most of their stock in containers these days. Why not replant another white birch? You are talking to someone who loves this tree species. Why not consider a clump birch or a cutleaf weeping birch? They are nothing short of outstanding when they get to maturity!

Q: I have a question about my dieffenbachia. It was doing fine until recently. I added some new soil, but when I returned to my office today, the bottom most leaf is almost completely yellow and three of the others are limp and droopy. I noticed that I accidentally used Schultz Potting Soil Plus for African Violets instead of a normal, nonflowering mix. Is the new soil causing this damage or is this the plant's way of losing the lower leaves? Is it supposed to lose leaves? (e-mail reference)

A: It could be from the soil you added. You may have spread it too thickly or it might be a different nutrient balance than what your plant needs. Either way, I would encourage you to remove the soil you added to see if the plant recovers.

Q: We have a beautiful weeping willow in our backyard. We love our tree, but it is so hard to mow underneath the tree because the branches weep to the ground. What is the proper way to trim these branches? (e-mail reference)

A: If there is a proper way, I've never known it! I have trimmed them to not be in the way of what you want to do, such as walk or mow under the tree. Remove the dead branches, which provide a nice supply of kindling for fireplaces.

Q: I have a mature lilac bush at the base of a small hill. I want to build a small retaining wall between the hill and bush. While digging a trench for the base of the wall, I found what must be some roots for this bush. There are three or more roots that have grown into the side of the hill. Can I cut these roots and not harm the bush? (e-mail reference)

A: The bush probably will not be affected by removing the roots as you describe. Be sure to make clean cuts to facilitate healing and limit the chance of disease taking hold. You may have to do some extra watering during the hot part of the summer to prevent wilting, but that shouldn't be a problem for the survival of the plant.

Q: I can't figure out what is wrong with my little princess spireas. This is the second time that I've replaced them. They are on the north side of the house and get full sun most of the day. We started out watering them every day, but they shriveled up to brown twigs and died. I got new ones this summer and planted them with lots of topsoil and manure because our soil is pure clay. They started shriveling up again, except for one that wasn't getting as much water. I realized that maybe I was overwatering. I put in soaker hoses and am watering every couple of days. They seem better, but every now and then they seem like they are going to shrivel up and dry out again. When I dig down a few inches into the soil, it feels moist. Only one plant has bloomed. I'm excited that the rest have some small, green buds. Any suggestions on what I should be doing differently and how often should I be watering them? Everyone else around me has beautiful little princess spirea shrubs, but mine are quite embarrassing. (Dickinson, N.D.)

A: This is one of the easiest deciduous plants to grow in our part of the country. You definitely have been overwatering the plants. Adding manure also may have contributed to the problem by adding excess salts. To do well, all the plants need is full sun and good drainage. Why not ask your neighbors what they are doing to make their plants look so good?

Q: How healthy would it be to eat tomatoes yielded from a plant that has rusty stakes in the soil the plant is growing in? I would imagine the rust would be seeping into the soil and thereby absorbed by the plant. Please advise what adverse effects could occur. (e-mail reference)

A: Nothing to worry about - the tomatoes may just be a little richer in iron, which isn't a bad thing. Enjoy the fruit because our summers are too short and the produce too limited. Remember how flat tomatoes taste from the supermarket in the middle of winter? These fresh-picked tomatoes will blow your taste buds away!

Q: Fifteen years ago I planted blue spruce on my farm near Kensal. However, the trees never have produced any cones or seeds. How old and mature must they be before they do? When nurseries produce special varieties, do they do it from seeds or from cuttings? How mature must deciduous trees, such as poplar, ash, oak or maple, be before they produce seed? (Kensal, N.D.)

A: If trees are under stress, they tend to get to the mature (sexually mature) stage faster than those that have most or all of their basic needs met. I've seen spruce that are not that old laden with cones, while others twice that age have very few cones. Unique varieties are asexually propagated through cuttings, grafting, tissue culture or other means, but not from seeds.

Q: I planted 10 different pepper plants which were supposed to produce yellow, orange and red peppers. The plants look healthy, but are much taller than usual. They are covered with blossoms, but there only is one pepper on the plants. What am I doing wrong? Is there anything I can do to make the plants produce peppers? (Ashley, N.D.)

A: Be patient. The tallness might be an indication of too much nitrogen-containing fertilizer or the plants being in partial shade during the day. It has been a tough summer for peppers, because they are fussier than others in the nightshade family. Temperatures that are too high or low can cause blossom abortion. Wide variations in soil water content also can affect blossom set. In addition, if they were set out too early, it may slow them down because of our weather being as unpredictable as it is. If all of the peppers you planted were of the bell (not hot) type, keep in mind that it takes longer for them to turn red, so they will be the last ones harvested this season.

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
Prairie Fare: Prairie Fare: A Taste of Brazil is Worth Trying  (2019-07-18)  Give beans a try on your menu.  FULL STORY
Use of Releases
The news media and others may use these news releases in their entirety. If the articles are edited, the sources and NDSU must be given credit.

Powered by Plone, the Open Source Content Management System