Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I have a nice sized Boston Fern, but the fronds seems to be a rather pale green. I do use fertilizer, and it has encouraged new growth. (I just got the plant this summer). I would like darker color though. Would a grow light encourage darker foliage? I should mention that I live in northern Canada,(Yukon) and our available natural daylight right now is very limited. (E-mail reference, Yukon, Canada)

A: Thanks for mentioning where you live -- it makes a big difference!! Yes, a grow light would make a big difference. I know they are available at many discount chain stores like K-Mart and others. Also, a small shot of iron may help as well. Look for the chelated form to keep it readily available to the plant. Ferns also benefit from regular misting with distilled water, especially during long winter months when the central heating system is drying the air down to 10 percent relative humidity or lower.

Q: Searching through the net about forsythia plants, I came up on your web page. I know you are in North Dakota where it gets pretty darn cold, but it also gets a little cold here in North Carolina. My question is, do I trim my forsythia the same here as you would in North Dakota? I only have one that I use to hide the gas line going to my fireplace and it has just about taken over the side of my home. It is about 6 feet in diameter and almost 7 feet tall. I don't want to kill it, but just how far back can I trim and when? ((E-mail reference, North Carolina)

A: Your damp cold can be almost as discomforting as our lower temperatures. I used to live in the South -- Georgia, Texas, and Arizona -- so I know a little about what goes on there. First thing, you probably don't have to worry about killing a forsythia that is as established as yours is. Years ago, I tried killing one by severe pruning and failed. I finally had to bite the bullet and grub the thing out of the ground, which was a lot of work. You can prune your plant at this time of year, and probably bring some of the prunings inside for a centerpiece, as they will flower easily once inside in a vase of water. I suggest cutting about one-third of it back as close to the ground as possible whenever the spirit moves and the weather allows. If you can, reach in with long-handled lopping shears and cut the largest canes at the base, then cut the top back to a bud to the size you want.

Q: Are there any peach varieties hardy to mid zone 4 or zone 3? If so, which nurseries carry them? (E-mail reference)

A: Your selection is going to be limited, but you might try Reliance or Wisconsin Balmer, both hardy in zone 4. I can't find anything for zone 3 or I'd be growing it myself! You can find these in the Henry Fields catalog. Phone 800-235-0845, or go online at www.henryfields.com.

Q: My neighbor just gave me a lovely red amaryllis. It is blooming wonderfully. My concern is what I should do with the flower after it is spent and begins to dry. Should I just wait or pinch it off? Also, I would like to know if this plant is dangerous for dogs to consume should a petal accidentally fall off and I not see it. I have a mini schnauzer I call "Mr. Mischief" because he gets into everything. (E-mail reference)

A: The leaves are not poisonous or toxic; the bulb itself is, so let's hope your mini schnauzer doesn't decide to gnaw on the bulb. In my opinion, it shouldn't be a problem. Once the flower has withered, cut the stalk back and allow the strap-like leaves to remain. Move the plant outdoors this summer, then at the end of August, bring it inside and allow it to dry down in a cool, dark location like your basement. About six to eight weeks later, bring it nto the light again and begin watering sparingly until new growth is observed. From that point on water regularly and enjoy.

Q: I have a nice Boston fern. The other day I found this frond on it with the perfect dots on the back. This is the only frond I saw on the whole plant like this. Could you please tell me what it is and if it is anything to worry about? (Tower City, N.D.)

A: First, thank you for an excellent sample. They are a rarity! What you are witnessing is the beginnings of the plant’s sex life, or reproductive cycle. However, on the Boston fern (Nephrolepsis exaltata ‘Bostoniensis’) those spores are sterile, or unable to propagate in this manner. All they are good for now is aesthetic value, so simply enjoy.

Q: What is happening to my African violets? I have been growing them for years and now they have just stopped growing and wilt until they are dead. I haven’t changed my method of care for them, except when I transplant them I have been using vermiculite. Could that be the problem? I can’t see that there are bugs on the plants. (Fessenden, N.D.)

A: The sample you sent had no evidence of any insects. It appears as if your African Violets are dying out from a crown rot fungus. This is brought on by over-watering (or the soil holding too much moisture) and wide temperature fluctuations. It is infectious, so if you handle a plant with these symptoms, it can be transmitted to other healthy plants upon handling. Although I cannot put the cause to the addition of vermiculite, I am still suspicious of it due to its high water holding capability. My suggestion: Throw out any symptomatic plants; repot in free-draining plastic pots; use only African violet potting soil; don’t over-water; and provide supplemental light via plant lights.

Q: I have a Canadian Red Cherry tree that has black growths all over it. At first I could cut off a few each year, but this year there must be 100 or more. Is there a cure? I hate to destroy the tree. (Rogers, N.D.)

A: Not likely at this stage of infection. You are better off removing the tree completely to keep it from being an infectious source to other trees in the area.

Q: We have built a ranch style house in a new development without a tree. I understand the city will plant a Fall Gold Ash on our berm next May. Please suggest a couple of trees for our yard and some bushes. We would like the trees in the back to shade our west side patio. Also, we are into color, especially reds. (E-mail reference, Grand Forks, N.D.)

A: I know just the perfect tree for shading your patio on the west side, one that I planted in my back yard to shade my patio. 'Embers' Amur maple gets about 20 feet tall and about 15 feet wide, has beautiful red fall color, and bright red samaras or fruits in mid summer. Another cultivar that is very similar is 'Red Wing' Amur maple. Other trees and shrubs I like are 'Redmond' linden, 'Heritage' river birch, and several viburnums -- the Nannyberry (V. lentago), Blackhaw (V. prunifolium), Arrowwood (V. dentatum, more of a hedge type plant) and finally, the American cranberrybush viburnum (V. trilobum). If you want size, then stay with the viburnum species (8 to 12 feet). If that is too big, then get the compact form (V.t. 'Compactum') which tops out at about 6 feet.

Q: I am looking for some varieties of pyramidal evergreens such as the Medora, but with more blue color than it has. I want something that will stay fairly narrow and not require much pruning to keep its shape. Do you have any suggestions for the northern South Dakota region? (E-mail reference, Aberdeen, S.D.)

A: Good question. My references list the following cultivars that may meet your interests

'Blue Arrow' - narrow, conical growth, intense blue foliage.

'Blue Haven' - neat and pyramidal in form, foliage is strikingly blue in all seasons, tends to be more open than 'Blue Arrow'. Heavy cone bearer.

'Moonglow' - a dense, pyramidal conical selection, intense bluish blue-green foliage, gets 20 feet tall by 5 feet wide

'Skyrocket' - bluish-green foliage, narrowest of columnar junipers available, getting 15 feet tall and 2 feet wide at the base.

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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.

Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu