September 18, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I live along a busy street that is sanded and de iced heavily during the winter. It gets plowed onto my boulevard and seems to be harming the grass. I completely reseeded the boulevard this past spring, using a drag, with a mixture of Kentucky bluegrass, fescue and rye, but didn't have a lot of luck. It is now full of crabgrass, barnyardgrass and foxtail. Is there a type of grass I can seed that will handle the sand and de icer? Is there something else I can do to minimize its impact on the grass? I'd also like to know where I could find pre emergent Tupersan (siduron) so I can try reseeding again this fall? (Fargo, N.D.)

A: There is a seed mixture called Boulevard Mix that is composed of the most salt tolerant cool season grasses. Many garden centers in the F M region handle it. Somebody out there should also handle Tupersan. The fact that you are getting a start this fall rather than next spring puts you at an advantage over the weeds. Try to get your reseeding completed by mid-September.

Q: My question has to do with my pothos plant. The other day I bought soil and repotted it into a larger pot but the soil looks awful. It is not soft and I cannot put my finger in it. Can I change the soil without harming the roots? How would I do that? Do you think Miracle-Gro is the best soil? I bet you can tell I am new at this plant thing. (E-mail reference)

A: Everybody has to start somewhere. I learn something new about plants almost every day. Try to find Miracle Gro or Schultz's potting soil. I have used both with great success. You can wash the soil off the roots and repot with one of the soils I mentioned or something similar. The soil should be porous, high in organic matter and either be sterilized or pasteurized (It should say on the bag).

Q: It has been a year since I replaced my sod in the back yard. It took well and I water it often but do not over-water. For the most part, it is green and acceptable with no patches or disease. It is the same soil-backed sod that my neighbor has but mine seems to have a lot of brown, dead grass giving it a green-brown look. It has been that way all summer, not just during this heat spell. Will this dead grass eventually disappear with aeration, thatch removal or top dressing with sandy loam? (E-mail reference)

A: Glad to hear it is doing ok. Mineral sod tends to be a little older than the peat backed sod, due to lower demand and use by landscapers. Yours should open up and take off after a fall treatment of core aeration and power raking, along with a shot of fall fertilizer.

Q: I have three potentilla plants that I bought from a catalog. They look beautiful every year but after four years they have never bloomed. They are planted in a sunny location and have good soil and drainage. It gets regular watering and feeding. Can you tell me what I'm doing wrong? (E-mail reference)

A: You are being too good to them. Allow them to suffer a little, or initiate traumatic stimulation by driving a straight edged spade into the soil about a foot or so from the base of the plant in two or three spots. You should get flowering next year or the year after at the latest. After four years they can pretty much fend for themselves. Water only during extended drought (three or more weeks without rain) and forget fertilizer.

Q: I've never grown melons before so I’m wondering; do you have sure fire tips as to when a cantaloupe is ripe? I've heard they get yellow bellied and twisted stems. I think I smelled an aroma when I was rustling the vines that make me think they are close to being ripe. I spent a nickel on the seeds last fall so it wouldn't take many to get my money back. (Gwinner, N.D.)

A: I go by the aroma while some go by the stem attachment to the melon. Both seem to work so pick your method and enjoy!

Q: What variety of potentilla should I plant? (Bismarck, N.D.)

A: There are over 100 cultivars of potentilla fruticosa. They range from Annette to yellowbird. Visit local garden centers to see what is available and popular. They come in yellow, red and white flower colors. The choice is yours!

Q: I planted some red maples in my yard this spring. Since then I’ve read that red maples are poisonous to horses. Do you know anything about this? (Pierpont, S.D.)

A: Not knowing the answer, I checked my poison plant book by Kingsbury. Sure enough, on page 216, it states: "Two cases of death in livestock, involving cattle and horses, after eating maple leaves have been reported from West Virginia." Based on that, I would either remove the trees or certainly keep the horses away from them.

Q: I recently bought plant food spikes (Miracle-Gro 6 12 6). Can I use it on aloe vera, pothos and a new baby cactus hawthornia? (E-mail reference)

A: If you haven't opened the package, take it back and exchange it for granular or liquid houseplant fertilizer. No houseplant on the face of the earth needs those spikes continuously stuck into their root zone.

Q: I planted hosta plants on the east side of my house for the first time this year. They did really well, probably doubled in size. I am wondering what to do with them this fall. Is there any special care that they need before or after frost or will new growth just break through next spring? I have the same question about daylilies. (Dickinson, N.D.)

A: After the fall frost nips the foliage back, you can cut it down or leave it there until next spring. It just depends on when you get ambitious. You don’t need to do anything, as far as care, because both species are as tough as crowbars!

Q: We bought and planted 75 lilacs a year ago. We watered them a lot until freeze-up. This spring we mulched them with wood chips and continued to water when it seemed they were dry but they really haven't grown much. The tallest is about 3 feet but most are shorter. Shouldn't they be taller by now? They look healthy with lots of green leaves. We want them to be a hedge to block the dust off our busy gravel road in front of the house. Are we expecting too much too soon? (Jamestown, N.D.)

A: Patience is hard to come by when one wants something to grow and fill in quickly. You are expecting too much too soon. The plants are getting established this year by putting energy into and developing a strong root system. The plants can then concentrate on top growth, which should begin next year. Hang in there; they will eventually fill the bill for you!

Q: The salvias in a large perennial bed have faded and I would like to cut them back to the ground so other plants can show. Can I do it at this time of year? (E-mail reference)

A: If they were healthy and vigorous this past summer, then it should not be a problem.

Q: I planted orange perfection phlox last spring in the back of my garden because the tag said it would grow 3 to 4 feet tall. It's blooming now but it's only about 18 inches tall so it's sort of hidden. Should I transplant it to the front of the garden? When would be a good time to do that? And if not, do you think it will grow taller? (Moorhead, Minn.)

A: You might want to wait another year. Sometimes it takes a couple of years for herbaceous plants to reach their full potential height. If it isn't up to height expectations by this time next year, then move it the following spring.

Q: We planted five bur oak seven years ago. They have not grown well. We are in the southeastern part of N.D. in heavy soil. I'm beginning to think we should replace them. What would you advise? What would be a good replacement? (E-mail reference)

A: Certainly if any tree has been in a planting site for seven years and has not grown well, one should consider replacing it. With what depends on what it is you’re looking for. Here is a short shopping list of trees that would roughly fit into the same category of your bur oak: hackberry, linden, black walnut, black locust, and common hornbeam. None grow very fast so if you are looking for that, you will have to go in an entirely different direction.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu