« Continue Browsing

e-mail article Print     e-mail article E-mail

Don Kinzler, Published May 21 2010

Fertilizer can be too much of a good thing

Q: I ordered a bleeding heart plant that was just starting to grow when it arrived. I potted it according to the directions. The soil I used was Jiffy Organic Seed Starting Mix, and I mixed in some Pennington All Purpose Plant Food 6-10-10. After two weeks, my plant turned brown. All it has is a tiny, brittle, thin stem. I took it out of the pot to clean off the roots, but there weren’t that many. I repotted the plant using the Jiffy Organic Seed Starting Mix without the extra stuff I used last time.

If this does not help revive my bleeding heart, what do you suggest I do to bring it back to life? I live in upper Michigan and have been sowing seeds inside until it is warm enough to put them outside. I did half of my plants using the Jiffy mix and the other half using the Jiffy mixed with a little of the Pennington 6-10-10. All the seeds planted in the Jiffy mix have germinated, but none of the seeds planted in the mix of Jiffy and Pennington have germinated. Should I stop using this mix? (e-mail reference)

A: The death of your bleeding heart and the lack of germination of the seeds are caused by no one else but you. In your attempt to shower kindness on your plants, you are killing them. When germinating seeds or transplanting crowns, there is no need to add any fertilizer because most potting soils have a sufficient amount of nutrients for normal plant growth.

The bleeding heart may have been immersed into a toxic level of fertilizer. Repot it using just the soil and wait patiently to see if something emerges. If there is life, it will begin responding in a couple of weeks with normal watering. I would encourage you to get your plants used to being outdoors by gradually exposing them to outdoor conditions during the day when the temperatures are in the 50s or higher and not too windy. Move the plants back indoors at night. Do this for about 12 to 14 days to toughen them up before planting them outdoors permanently.

However, be sure the danger of a hard frost is past.


Q: Are the whirly birds falling from my tree poisonous to my dog? He loves to eat them. (e-mail reference)

A: Those whirly birds are seeds from a maple tree and have never been known to poison a dog.


Q: We planted three Black Hills spruce trees in our backyard in 2007. One of the trees has developed a long, central lead branch with two long branches just beneath it. The top of the tree is not symmetrically balanced like the other two trees we planted. Should we trim the main upright branch and the two side branches or just leave it as is? When is the best time to trim these? (Fargo)

A: First, congratulations on selecting the Black Hills spruce and not the Colorado spruce for your planting! Yes, you can go ahead and trim those branches back. Now is a good time to do this. These are some very good-looking trees that will be an increasing asset to your property as they continue to mature. Just don’t overwater or overfertilize them.


Q: The grass in our green space area next to our preschool playground needs to be reseeded. I’m wondering what mixture of grass seed you would recommend for such an area. It gets lots of traffic from the little ones and is partly shaded by a church and large trees. (Moorhead)

A: Look for a package labeled as playground mix or athletic field mix. These contain mostly Kentucky bluegrass and perennial ryegrass in equal proportions by weight with some creeping fescue mixed in. With the shade you mention, you would want to get a shady lawn mixture and incorporate that into your overseeding efforts if you were not able to get a separate package of creeping red fescue.


Q: Last spring, I planted some dark horse weigela bushes. We had a very harsh winter with a lot of snow. All I am seeing on my bushes is the branches from last fall. I don’t see any blossoms on them at all. Will they come back, or do I need to replant? Do these bushes grow from the ground up every spring or from the branches themselves? (e-mail reference)

A: You didn’t say where you live. These bushes are hardy up to Zone 4. If the winter was very cold, it could have killed the aerial (branching) part of the plant. In this case, assuming the roots were well insulated from a deep snow covering, you should get regrowth from the crown of the plant. If the lows occurred when the snow cover was lacking, it could have killed the plants.

Normally, they will survive the winter in the right zone and with normal winter weather (whatever that is) and grow from the branches with just a little nipping out of the random winter-killed branches.


Q: I split and transplanted a maroon-blooming peony bush. It was very large and very old. I dug up a large rootball with about 15 eyes on it. Some of the eyes were just starting to peek through the soil, and some were not up yet. I planted the whole rootball with a lot of loose soil. They are really growing now.

Now knowing that they should have been transplanted in the fall to develop a root system, should I not allow them to bloom this spring so they can develop a root system? If they do get nice buds, should I let them bloom? (West Fargo)

A: Let them go and enjoy. Many before you have done exactly the same thing with great success. This fall, allow the foliage to remain until a killing frost arrives.


Q: What product can I use to kill quack grass in an iris patch? (e-mail reference)

A: Vantage and Grass Getter are two products that are available. Look for any herbicidal product that is listed as a grass controller. Check the active ingredient of the product. It should contain Sethoxydim to be selective. The effectiveness is increased by mixing it with a surfactant, which usually is sold in combination with the herbicide.


Q: We are attempting to revitalize our lawn and have read that it requires a soil activator. We have been unable to find a dealer in the Bottineau or Minot area that handles it. Can you give us any leads? (e-mail reference)

A: Selling soil activators is snake-oil marketing. It is your money to do as you wish, but I would suggest a soil test that is sent to our soil-testing lab on the NDSU campus. Follow the recommendations from that test to add the needed nutrients. That, along with other good cultural practices, is all that is needed to have a revitalized lawn. You can contact the lab at www.soilsci.ndsu.nodak.edu/services/Testing/soiltesting/soiltesting.html.


Q: I have some lilacs that bloom every year. They are very tall and planted in a row. For the most part, they only bloom on top. I have seen so many lilac bushes that are round and full and covered in blooms. How can I get mine to bloom like that? (e-mail reference)

A: After they finish blooming this year, cut them back before new growth begins.

At the same time, take a straightedge spade and drive it into the ground around the outer spread of the lilacs to sever some of the roots. This usually stimulates the plants into setting more flower buds for the next growing season.


Q: I have a question about getting rid of a cotoneaster hedge. What is the best way to kill it? It was cut to the ground about two years ago but is growing again. I have evergreen trees about 20 feet away from this hedge, so will it hurt the trees if I use a herbicide? Do you have any other suggestions on how to get rid of it? (Battleview, N.D.)

A: You can spray it with glyphosate when it leafs out. If you don’t have any spray drift, your evergreens will be OK. Another approach is to let it come into full leaf this spring and then cut it down with a chain saw. Nail anything green that shows with glyphosate after that, and you should be free of the hedge!


Q: We have a 10-year-old mock orange plant that we prune every year in the fall.

We have pruned it early, too. Will we ever get flowers? We have had a few flowers down low on occasion. Do we have to stop pruning it to get a nice set of blossoms? (e-mail reference)

A: You should prune it immediately after flowering to have blooms the following year. Also, remove the oldest canes every three or so years. Cut it back to the base of the plant and get rid of the twiggy inside wood by cutting back to a crotch. Never cut back the ends of branches or else an ugly broom-shaped shrub will be the result.


Q: I was wondering if I could cut a large root on my red maple that is growing on top of my lawn. It makes it difficult to mow. Will cutting the root harm the tree? (British Columbia)

A: Cutting a single root out of an otherwise healthy, mature red maple will not harm the stability or vigor of the tree.


Q: If a person were to apply a grub control product to control nightcrawlers, when is the best time to do that? (e-mail reference)

A: Right now. It takes time to work into the soil, so the sooner the better.


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.