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November
25, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: Last spring our
lawn came up nice and green, but there was a lot of quack grass mixed
in. Is there a way of getting rid of the quack grass without killing the
other grass or using Roundup? (West Fargo, N.D.)
A: Sorry, the answer
is no. Roundup kills quack grass, but needs to be repeatedly applied.
However, it comes back even in the best of lawns!
Q: Is a grapevine
the only plant to produce fruit without first producing blooms? (e-mail
reference)
A: It does produce
flowers; you just don’t see them.
Q: I have noticed
little white specks on the leaves of my piggyback. At first I thought
I may have splattered paint on it while painting recently. Upon closer
examination, I see a sticky white substance at the base of the plant,
actually in the roots. I cleaned the leaves with water and a bit of dish
soap. They look better, but the plant seems to be failing. Any idea what
is happening? (e-mail reference)
A: The plant is
likely responding to the dish soap treatment. It should recover.
Q: I have purple coneflowers
in their second year of blooming. The petals are drying out and turning
brown. Could this be a symptom of overwatering? (e-mail reference)
A: Yes, they can
get along very nicely on what nature provides because they are prairie
plants. They should be fine if you back off on the watering. If anything
can kill these plants, too much water will.
Q: What can I do about
the “neckiness” of my African violets? I don’t want
to propagate more, just correct the long necks on the plants, which continually
flop over. (e-mail reference)
A: My reference
book for African violets was written by Melvin Robey. The name of the
book is “African Violets - Queens of the Indoor Gardening Kingdom.”
He has several pieces of advice that may help you. Cut off the main
stalk of the plant at the soil surface. Trim the stalk so that only
2 to 2.5 inches remain below the rest of the plant. Scrape the stalk
with a knife or spoon handle to roughen the plant’s cell tissue,
which encourages root formation. Allow the stalk to air dry for 30 minutes
and then place the stalk in water, vermiculite or perlite until new
roots form. Transfer the plant to a pot. Wait two weeks and then begin
feeding the plant a high P and K plant food. This will encourage the
plant to start flowering again. There are two advantages to using this
technique on your aging African violets. The plants will begin flowering
very soon after being repotted and the technique will restore vigor
to an old plant, which means you’ll be able to enjoy its beauty
for many more years. Robey gave the book to my wife for her birthday
back in 1983 when we were living in Saudi Arabia.
Q: My wife purchased
some dwarf lilacs to plant next to our house. How close to the sewer outlet
can we plant them? I hear the roots will grow through the pipe. How long
do these roots get? (e-mail reference)
A: The roots will
grow into sewer and water lines that leak. The roots will follow the
path of least resistance where water, air and nutrients exist. Planting
the lilacs 8 to10 feet away from the sewer line should be more than
enough distance.
Q: I have creeping
clover that is taking over my yard. All the stems emerge from a single
point at the base and spread out. It has small, round yellow blooms. Is
it susceptible to any specific weed spray? I’m also looking for
a low-growing ground cover to go between stepping stones that is durable
enough to handle some foot traffic and zoned Region 4. I have eliminated
moss, as this area would get a fair amount of sun. (Sykeston, N.D.)
A: Sedum and dwarf
yarrow quickly come to mind. They are not known for their foot traffic
tolerance, but both are fairly persistent and should recover. As for
the creeping clover, Trimec will take it out with repeated applications.
Q: I planted a tomato
plant (can’t recall the name, but it grew small, cherry like tomatoes).
It grew a lot of tomatoes, but almost all of them fell off while still
green. Any ideas what caused the problem? (e-mail reference)
A: Usually fruit
drop is caused by fluctuations in water availability or temperature
swings. It could be the plant was not nourished sufficiently to support
the fruit load.
Q: My daughter and
I both purchased devil’s ivy plants. We only water when the soil
becomes dry and don’t overwater. My daughter’s ivy is growing
much prettier than mine. Mine has four runners while hers has many more.
What am I doing wrong? Her ivy appears to be crying at times. She does
not overwater, but drops fall from the leaves like teardrops. (e-mail
reference)
A: It could be such
things as the amount of light, heat, drafts, water source, temperature
or using different containers. The crying you are referring to is from
a small opening in the tips of the leaves known as hydathodes. Apparently
your daughter’s plant is blessed with an abundance of hydathodes
that pass the water from the interior of the plant to the atmosphere.
It’s nothing to worry about.
Q: We planted a crab
tree last year. It got blossoms this year and very small red fruit, but
the leaves were very small. The tree looked fine except for the bare appearance
because of the small leaves. Any clue as to why the leaves were so small?
(e-mail reference)
A: It is the new
growth that counts. Everything will even out with time, so don’t
worry. The fruit will not get much larger because it can’t go
beyond its genetic potential for size and color. Last year’s environmental
setting probably had an impact on the leaf size of the older growth.
Q: I had to move some ash trees at a bad time of year. It was late June
after they were totally leafed out and thriving. If I didn’t move
them, I would have had to cut them down. I have eight years of care invested
in them, so I thought it was worth the chance. I kept them well-watered
the first summer. The trees seemed ok even though they lost their leaves
early in the fall. Last summer they leafed out fine, but a little late.
I kept them watered, but they again lost their leaves early. This summer,
only a few branches had leaves. I attributed it to a late frost, but they
didn’t recover like my other trees. Are they a lost cause? (e-mail
reference)
A: I wish I were
enough of an optimist to say that everything will turn out ok. I really
doubt that it will. Keep in mind that the majority of the feeder roots
were removed when the trees were moved, so the trees were essentially
living on what stored carbs were in the remaining supportive roots,
crown and stem.
Q: I suspect I have
aphids in my asparagus. How can I tell for sure? What should I spray it
with and how often? (e-mail reference)
A: Aphids should
be visible to the naked eye. They are very vulnerable to Insecticidal
Soap, which is safe to use. Be sure to get good coverage to assure control.
Q: I have a huge maple
tree in my yard. It was planted about 45 years ago. The leaves used to
be a beautiful red color, but the last few years the leaves have been
green. Now some branches have a very pale color. (Moorhead, Minn.)
A: The problem could
be anything from root rot, vascular disease and borers to cankers or
more. I suggest you contact Kelly Melquist, an International Society
of Arboriculture certified arborist, at (701) 729-6899. He has been
working for decades to save trees around our region and has done a commendable
job.
Q: I need advice on
how to store canna and glad bulbs this winter. I’m also wondering
what I should look for when I buy a plant light. (Audubon, Minn.)
A: The corms should
be dusted with sulfur and stored dry. You can use sphagnum peat if you
wish. Put the bulbs in paper bags and store them in a cool (50 to 55
degrees), dry place. Plant lights are self-descriptive. Flowering plants
such as African violets need more light than a philodendron, which is
valued mostly for its foliage. Consequently, the philodendron could
get along with light at a greater distance away, while the African violet
would need to have the light source much closer. Fluorescent technology
has come a long way in recent years. It boils down to what it is you
want the light to do. Do you want the light to augment natural indoor
lighting, produce flowering plants or grow vegetables?
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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