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November
11, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I’ve got
some trees/shrubs that are starting to look bad. You often advise people
to contact a certified arborist (I think that’s the term you use).
How do I find one? (Fargo, N.D.)
A: I have direct
experience with two people in Fargo. Kelly Melquist, (701) 729-6899,
is very good at diagnosing tree problems and finding a possible solution.
James Danielson, Cougar Tree Care, has the uncanny ability to remove
limbs or entire trees with the competency of a surgeon. Danielson can
be reached at (701) 729-7208.
Q: Two young evergreens
have had the top leader snapped off. What will happen to the tree and
can anything be done to promote the growth of another main leader? (Dickinson,
N.D.)
A: The evergreen
will go through a “competitive factor” now that apical dominance
has been removed. You can break off all but one lateral branch or wait
to see which one naturally takes the lead. Once a leader has been established,
prune the others back and stake up the natural leader for a growing
season.
Q: I have noticed
this year that the linden tree in our yard is attracting a lot of flies.
Should I be concerned about the tree’s survival? (e-mail reference)
A: If you look closely,
I think you will see some insects known as aphids or scale on the stems
and leaves. These insects excrete honeydew from their feeding, which
is a strong attractant for flies, ants and yellow jacket wasps. Aphids
are easily controlled with contact sprays such as Insecticidal soap
or Sevin. Scale is more of a challenge to control. The best route is
to apply dormant oil next spring before leafing takes place. You might
want to contact an International Society of Arboriculture certified
arborist to inspect the tree and give you a recommendation.
Q: What can I do to
get rid of creeping jenny in my yard? Is there a spray that will not kill
the grass? Also, I want to plant a couple Aspen trees. What time of year
should I plant them? (Bowman, N.D.)
A: Trimec will kill
creeping jenny with a couple of applications about six weeks apart.
You will probably get some re-growth next spring, but with another application,
it should be under control. Aspen, or any trees for that matter, can
be planted anytime they are containerized. In fact, if a local nursery
has the trees growing in containers, now would be the best time to plant
because the soil is warm, there is no or very little top-growth taking
place and the roots will get off to a good start for the next season.
Q: I recently planted
two dogwoods in my front yard. After three weeks, the leaves turned bright
red and then died and fell off. The branches appear healthy (moist and
flexible). Is there a possibility they will come back or should I replace
them? (e-mail reference)
A: As long as there
is a twinkling of life in the limbs, there is a chance that they will
come back. Don’t overwater or fertilize.
Q: I planted a Northwood
maple tree a few years ago. It was doing fine, but now most of the tree
has developed brown spots, especially on the edges. Some are almost all
brown. I have some Daconil I used on a different tree and wonder if it’s
too late to use on the maple this year. Should I use Miracid? Also, I
would like to roto-till. How deep can I go without hurting the root system?
I would probably mulch with sawdust. For winter, can we cover the tree
with sawdust? (Becker County, Minn.)
A: Keep the roto-tiller
away from the base of the tree! It could cause irreversible damage.
It sounds like the tree was planted too deeply or is getting too much
water. Reset the tree, back off on the watering or both! There is no
problem using sawdust if it was composted. If it is raw sawdust, you
will have chlorosis problems. You can correct that with additional applications
of nitrogen fertilizer. Covering them with composted sawdust would be
acceptable, but protect the plants from voles and other varmints with
wire hardware cloth.
Q: What can be done
to keep deer from eating zucchini and cucumbers out of the garden? I’ve
heard of a mixture of milk and eggs that is poured over the plants to
keep the deer out. Have you heard of such a thing or do you have another
option for her? (e-mail reference)
A: I have heard
it and about a half dozen other concoctions as well. Advocates all swear
that each one works. In reality, they all work up to a point. Deer are
creatures of habit and are not easily spooked or deterred when they
are hungry. Human hair, Irish Spring soap, predator urine and hinder
are also highly touted. In reality, the only reliable way to keep the
deer out of the garden is with an exclusion fence that is electrified.
If an electric fence is out of the question, then the grab -bag mix
of practices mentioned should be alternated to keep the poachers off
balance!
Q: Can you please
give me a tip for extending, beyond one or two days, the life of Annabelle
hydrangeas? I have flowerless neighbors who could sure use some of my
excess. (e-mail reference)
A: Hair spray usually
works quite well. Fog it over the head of the flowers. You can also
acidify the water with unbuffered aspirin. The aspirin will keep the
stems from plugging because of bacterial development. Florists usually
have several materials available that are effective in extending the
life of flowers.
Q: I would like some
information as to why my son’s table peas turned brown at the base
of the plant this year. Could it have been some sort of blight? (e-mail
reference)
A: It was likely
a fungal disease known as Phytophthora, the result of wet, cool weather.
Hopefully there will be better environmental conditions next spring.
Q: I have two bougainvilleas
that bloomed this spring and summer with many blooms. They are still covered
with blooms. The leaves, however, are turning yellow and falling off.
They over wintered in the house this past fall and winter. They even bloomed
while in the house. I am doing nothing different from last year when they
were healthy. I feed them every two weeks and water religiously. (e-mail
reference)
A: The plant is
probably attempting to go into dormancy because it needs a rest! Let
it dry completely this winter by watering only occasionally. Next spring,
as new growth begins to break, go back to your original watering cycle.
Q: I have two flowering
crabs in my backyard. They flowered beautifully this spring but then began
to look sick. The berries and leaves had a rusty layer that could be rubbed
off. Two other trees in my neighbor’s yard looked the same. (e-mail
reference)
A: Sounds like cedar-apple
rust. Clean the area thoroughly this fall and spray a lime-sulfur mixture
early next spring while they are still dormant. Spray with a Bordeaux
mixture after the leaves unfold. Repeat the fungicide spray again 30
days later. That should provide protection. In the meantime look for
the offending alternate host, junipers. If you see an orange globular
growth on the trees this fall or early next spring, pick them off and
dispose of them. That is the source of infection on your crab-apple
trees.
Q: Three summers ago
a friend gave me a slip from a grape vine. I thought for sure that I had
killed it the first summer because it looked sickly, but it survived.
Last summer I purchased an arbor, planted it and had maybe a dozen small,
purple grape clusters. This year, it looked like I’d been invaded
by a killer grape! It totally took over the arbor and tried to latch on
to the nearby tartan honeysuckle. When and how do I prune the offending
plant? (Detroit Lakes, Minn.)
A: Grapes are typically
pruned in late spring before leaf-out takes place. Don’t be afraid
to cut it back hard. It sounds like a beta grape, which is as tough
as nails. I have one myself and it does the same thing, even with the
hard pruning in the spring. Cut it off the shrubs and trees you don’t
want it climbing on. You want to cut it back to about an 18 to 24 inch
stub next spring. Don’t worry, it will take off again. I’ve
had mine for 18 years and have not given it one bit of encouragement!
Q: What can you tell
me about fall transplanting of painted and Shasta daisies? What about
transplanting (fall) perennial lupines? (e-mail reference)
A: Dig after they
have been hit with a couple of hard frosts. Plant them in the desired
site with added peat moss to backfill the soil and water in well. Mulch
the crowns with peat moss after the ground has frozen, but before winter
sets in. Lupines are another story. They have deep roots, which make
them difficult to successfully transplant, but nothing ventured, nothing
gained. Give it a try using the same transplanting directions as the
daisies.
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
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