Advertise in Print | Subscriptions
Published June 04, 2010, 12:00 AM

Why are my blue spruce trees turning yellow?

Q: I planted eight blue spruce trees a year ago. This spring, I have noticed that two of the trees have a yellowish hue. They do not feel brittle, but they do not have the rich green and blue of my other trees.

By: Don Kinzler, INFORUM

Q: I planted eight blue spruce trees a year ago. This spring, I have noticed that two of the trees have a yellowish hue. They do not feel brittle, but they do not have the rich green and blue of my other trees. The two trees in question are planted in front of a neighbor’s horse barn, where there is horse manure piled up. I don’t know if the old manure bothers the trees or if they are getting too much water. Do you think the yellowing tint means they are dying? Is there anything I can do to salvage them? How will I know if the trees are dead?

Do you have any suggestions for replanting blue spruce in the same location if these two are dead? (Pennsylvania)

A: Blue spruce is very much at home in your area and even here in North Dakota.

Blue spruce has a dislike for standing water and/or high-soluble salts. I’ll bet the soluble salts in that area are very high and will keep the trees from developing normally. If they do die, the high-soluble salts will not be the direct cause. Stressed trees invite insect pests to come in and finish the suffering victims! If the trees are not dead, I would suggest carefully moving them to another location in your yard.

Before replanting, excavate as much of the old manure out of the area as possible. Get some topsoil from another location on your property or buy some to replace the removed manure. Make sure the area has good drainage before planting.


Q: Are the leaves on a plum tree edible? How about other fruit trees?

(e-mail reference)

A: All members of the Prunus spp. have poisonous leaves and stones inside the fruit. As for other fruit leaves, I would have to address each one individually.

Apple leaves and seeds are poisonous as well and considered to be cyanogenic.


Q: I have a large white dogwood tree that grew adjacent to a large oak tree. The oak tree had to be removed. The stump began to decay below the ground, so now the dogwood is starting to lean away from the old oak tree site. I assume the dogwood roots are entwined with the oak roots that are now decayed. Other than propping up the dogwood and filling in the hole left from the decaying oak, is there anything I can do to stop the leaning? Will the dogwood put out new roots to anchor itself when the stump is gone? (e-mail reference)

A: Stake the tree to a vertical position for the time being.

Roots eventually will fill into the fresh soil and decaying organic matter from the oak roots. Be sure the staking material is not made of wire. There are straps that can be used that are available at most garden centers and will not cause damage to the bark of the tree.


Q: I have 60 arborvitaes that I planted about six years ago. We had a huge storm about a month ago. I didn’t lose any (uprooted), but many are now leaning over.

I am not sure what to do about the problem. I am a novice gardener at best.

However, I am not averse to putting in some major work to restore them. My thinking was to try pulling them upright using stakes in the ground. I would pull them straighter every few days. Is gradually pulling them upright the right thing to do? (e-mail reference)

A: The only problem is that you waited so long to do it. It is recommended that the rerighting of a tree should take place as soon as possible. Get out there this weekend and put tension on the lines to pull the trees upright. Adjust the tension a little every day until they are straight.


Q: Some time ago, deer wrecked my Deborah maple by scraping all the bark off the trunk. Last summer, the tree did not produce leaves. However, there were three or four shoots that came up beside the trunk and had the most beautiful color all summer. This spring, the tree seems to be dead, but the shoots are alive and budding. What should I do? Should I dig up the tree? Should I cut down the tree and let the shoots try to grow or give up because of all the deer? This tree was so beautiful the first year. We now have protection around the tree. We live on a farm, so we can put a wire structure around it. (Tappen, N.D.)

A: The tree should be replaced. The shoots you see coming from the roots are not from the same cultivar. These are grafted trees that have a different root stock from the top, which is what you want. The suckers will grow, and with some work on your part, you may get something that may or may not resemble a tree. I’d suggest going out and getting the one you want. Keep the tree protected until it gets big enough to fend for itself.


Q: I have a clump river birch that I planted last spring. It almost doubled its size before the winter started and developed plenty of new branches. It is in a space where the lower part of the tree is shaded and the top gets plenty of sun.

The issue I have is that it is not budding yet (late April). The branches seem to be alive because they are not brittle. The soil is moist, although I did not start watering until two weeks ago. I put Miracle-Gro granules around it about a week ago. It seems like the tree is in a dormant stage. We have had a rather uneven spring. We have reached 80 degrees a couple of times and went back to the mid-30s some evenings. Any recommendation about what I should do to get my beautiful tree to be full of leaves again? (Chicago)

A: Your river birch should be leafing out by now. I’m speculating that you purchased the tree from a national chain. The retailer may have purchased the stock from a nursery several zones south of Chicago. The length of day may be confusing the tree and delaying the breaking of buds. It also may be planted too deeply. This often is the case where the owner thinks that planting a tree deeper will make it more stable and able to reach deeper for moisture. The salts may be excessively high in your soil, which would slow everything up. The primary buds may have been injured or killed with the fluctuating temperatures.

In reality, there is nothing you can do except wait. Don’t compound the problem by overwatering or trying to push it with fertilizers. If the tree is going to emerge from this dormant state, it will do so on its own. If the tree hasn’t foliated by Memorial Day, replace it.


Q: I have been looking all over the Web to see if Veronica speedwells are toxic to dogs. Do you know the answer to this? (e-mail reference)

A: In going through my references, I cannot find any indication of it being a poisonous plant. Poisonous plant references are centered on human and livestock poisonings, so what might not make us sick or kill us could end up being toxic to dogs, much like chocolate. However, it is in the figwort family (Scrophulariaceae). Many in this family contain what are known as cardiac glycosides that have a negative impact on the heart. Whether or not the Veronica contains these glycosides in a toxic concentration is not known. Plant it if you like, but try to keep your pet away from it.


Q: A year ago, there was an accident, and my creeping juniper got burned. It is coming out of it, but the brown ends are still there. Can they be pruned and is there a certain time of the year to do it? (e-mail reference)

A: They can be pruned, and now is the best time of year to get it done.


Q: When I was a small child, my grandmother had bleeding heart plants. She also had a story to go along with the plant. She would take one of the hearts apart into seven pieces. The two outer pieces are swans and I think the next two were slippers. I’m not sure what the next two were, but the last piece is a candle.

Do you know anything about this? (e-mail reference)

A: I’m sorry, I don’t. However, I’ll bet that one or more readers of the column will know. When I hear, I’ll certainly let you and everyone else know. The story sounds interesting. Thanks!


Q: I have a question about ground ivy. Half of my backyard is infested with it.

I’ve read about using Trimec, but my concern is the trees. I have five mature trees. Two are black walnuts, and the rest are a pecan, red oak and sweetgum tree. I also have about a dozen eastern redbuds and one dogwood. Will the Trimec have an adverse effect on these trees? Would it be better to rely on a spot spray treatment instead of using a garden hose sprayer? I’ve been pulling up the ivy for about a month, but it is a losing battle. I would keep the spray away from the trees, but I’m worried about the effects of root absorption. If not Trimec, what do you think the safest chemical alternative is? (St. Louis)

A: Trimec has an ingredient that is root active, so it will have a negative impact on sensitive trees, such as the dogwood and redbud species. If you follow the label directions, spraying the ivy once a season should help you get it under control without harming your sensitive trees. I highly recommend spot spraying rather than the garden hose application because people get carried away with the garden hose spraying. I wish there was something equally as effective as Trimec, but I don’t know what it would be.


Q: We planted a red maple yesterday. The root ball was very small. The caliper was 3 inches. Is this normal? Should we do anything special for it? I think it might blow over in the wind because it hardly has a root system! (Utah)

A: If the caliper size was 3 inches, then the minimum ball size should be 32 inches in diameter, according to American Nurseryman Standards. Ball sizes always should be of a diameter and depth to encompass enough of the fibrous and feeding root system as necessary for the full recovery of the plant. The recovery may be slowed, limited or not at all with anything less. Overwatering and fertilizing will not substitute for an undersized root ball.


To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu.

Tags: