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April
8, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I have a young
mountain ash tree. Recently I noticed the bark has been chewed off the
south side of the tree to a height of about two feet. I’ve wrapped
the tree in burlap to protect it from the sun. Is there anything else
I can do? Is there a chance that it may survive the damage? (E-mail reference)
A: There’s
a very good chance it will survive. The tree is young so it should have
plenty of vigor to heal, for the most part, this summer. I suggest removing
the burlap this spring to allow air to get to it and aid in the healing.
Next fall, wrap the trunk in burlap before the snow flies. Wrap it to
the first set of branches to protect it from gnawing varmints!
Q: I planted two ponderosa
pine trees late last fall. They were in nice shape but in mid-winter they
started turning brown. Should I have sprayed them with a defoliator? Will
they survive? The needles are still bendable. (E-mail reference)
A: Never use a defoliator.
Instead, use an anti desiccant like Wilt Pruf. The trees are showing
some moisture loss from winter stress. I'm confident they will survive.
Q: I have a maple
that has holes around it. I see woodpeckers there all the time. What can
I do to protect the tree? (E-mail reference)
A: Try to annoy
the woodpeckers in some way by using aluminum foil, scare balloons,
tanglefoot near the tree parts where they like to make holes, or by
spraying them with a garden hose.
Q: I purchased a good
number of bulbs last fall. I intended to plant all of them but I got busy
and only planted half. What can I do to store these bulbs or can I still
plant them and have them come up next year? (E-mail reference)
A: I doubt that
you can successfully store the bulbs for another year. I suggest getting
them planted as soon as possible and take whatever results you can get.
Q: We have some type
of arborvitae on the south side of our home which was here when we came.
They are about 18 years old. They are about three feet from the foundation
and are five to six feet tall with trunks about five to six inches in
diameter. We are concerned about damage to the foundation of the house.
Should they be removed? If not, should they be pruned? (Corsica, S.D.)
A: Arborvitae
will not cause any damage unless you have a wet, leaky foundation. If
they are complimenting the architecture of the house or providing some
function, there is no need to remove them. Remove them if they are overpowering
the house or looking ratty. They can be pruned in the early spring,
prior to new growth.
Q: I have a new spider
plant I started from a baby about three weeks ago. How long will it take
to mature? Is there enough space in a four inch diameter, three inch deep
terra cotta pot for it to reproduce? (E-mail reference)
A: Probably, but
you’ll have to wait and see. If it gets potbound without reproducing,
then move it to a larger pot. The length of time it takes to mature
varies with the vigor of the individual plant, the kind of care it gets
and its location in the house. It could be a year but certainly not
longer than two.
Q: I have two poinsettias
that nearly died after Christmas. We forgot to water them for over a month!
As you can imagine, nearly everything died. After a lot of work, they
are finally growing new leaves. My problem is that the new leaves aren't
growing from the main stems; they are suckers. What should I do to get
this plant to look like new and make it bloom again? (E-mail reference)
A: Continue caring
for it as you have been. When all danger of frost is past, plant it
outdoors in an eastern or northern location. Most poinsettias respond
beautifully from such treatment. You can take cuttings from it this
summer or bring it indoors and begin the short day treatment toward
the end of September, to bring it in flower.
Q: I have a hibiscus
plant which was in constant bloom for a couple years. I read an article
by a horticulturist that said I should cut it back, set it in a dark place
and water infrequently to give it a rest over winter. I did that, but
now I have a thriving plant that will not flower. (E-mail reference)
A: Give it more
light and less fertilizer.
Q: We have a huge
cottonwood behind our house. This tree is so large it looms over our home.
A man who painted our home told us that cottonwood trees are known for
snapping and falling down. Is this true? (E-mail reference)
A: The painter may
know what he is talking about. They are notoriously weak wooded trees.
I would suggest that you get an International Society of Arboriculture
certified arborist out to inspect the tree and assess the potential
hazard it may pose.
Q: My girlfriend bought
a new house so I moved her very large euphorbia cactus. It looked fine
when I left but when she came to check on it five hours later, it was
dead. Is this possible? (E-mail reference)
A: Isn't it amazing
how easily we can get into trouble with the women in our lives? It could
only be possible if the plant was moved, without protection, when the
temperatures were too low.
You might offer to purchase a replacement along with a box of her favorite
chocolates and a note of apology. Hope that works!
Q: I planted 25 rose
bushes and half seem to be wilting. I put fertilizer in the holes before
I planted and sprinkled some on the ground. Someone told me the roots
were burning and I need to put a soaker hose on them to try and wash out
the fertilizer. The plants do perk up after they are watered for an hour
or two. Would it hurt to put a soaker hose on them to flush the fertilizer
or is there another problem? (E-mail reference)
A: You are doing
the correct thing by attempting to leach the fertilizer salts out of
the root zone. I suggest spraying the foliage with an anti desiccant
to keep them from transpiring water through their leaves, which should
keep them from wilting. Some of the wilting is probably due to the tenderness
of some new growth. Once the plants have adapted to their new environment,
in a week or two, the wilting should stop. Just be sure to keep the
water off the foliage.
Q: I have a hibiscus
plant which blooms a lot but it keeps losing leaves. I have it in the
west window. What care does it need? (Maddock, N.D.)
A: I can't really
tell what your hibiscus is suffering from. Is it in a free flowing container
and do you pour out the excess water? Has it been a while since you've
repotted? Is there any evidence of scale insect activity on the stems?
Hopefully, you can take action on one of these factors to correct the
problem.
Q: My problem concerns
a section of my yard where the ferns and grapevines have turned yellow.
We didn’t have a lot moisture last year so I don't think that’s
the cause. I've had the ferns for several years. They are on the north
side of our garage but get morning sunlight. The grapevines are farther
out and get more sunlight during the day. Could there be a lack of some
minerals in the soil? (York, N.D.)
A: Yellowing foliage
on two different genera of plant material is an indication of something
abiotic. My first suspicion is usually herbicide drift, through the
soil or air. If no herbicides have been used in or near that area, then
it is a coin toss as to what it could be. You might try experimenting
with Miracid, an acidifying water soluble fertilizer that would provide
a shotgun supply of nutrients. That would correct the problem if there
is a nutrient deficiency.
I don't know what
else to suggest.
Q: I used to own an
aloe vera plant. It grew babies so I gave one to my mother. My plant developed
a fungus which eventually killed it. The plant I gave my mother eventually
had a baby which she gave to me. Within one week of repotting, the plant
developed a light, fuzzy look over the top of the dirt. The plant has
adequate drainage. I can’t figure out what is causing the fungus,
let alone how to get rid of it. Can you shed some light on this problem?
(E-mail reference)
A: Something has
not been properly sanitized or sterilized. It could be the soil, container
or the planting tools if any were used. It’s likely a saprophytic
mold that is growing over the soil surface. When it gets to living plant
tissue, it becomes a parasite which destroys the plant. Use only sterilized
or pasteurized media in a clean, preferably new container. Do not over
water or allow the water to stand in the saucer.
Q: I have assumed
the care of a large jade plant that is completely infested with scale.
To wipe the surfaces of all leaves and stems with diluted rubbing alcohol
would be almost impossible. The plant is important so I would like to
save it rather than start new. It is in a public place so the treatment
should be as people safe as possible. I have read that using Dimethoate
as a drench is an effective control for scale but it is not licensed for
this use in Ontario. Also, I cannot find any reference that Dichlorvos,
which is present in no pest strips, is an effective control for scale.
(E-mail reference)
A: No pest strips
enclosed in a large trash bag would do the trick if used over a weekend.
Horticultural oil might work but I would try a small section first to
see if any damage occurs. Spraying with rubbing alcohol might work and
be the safest thing to do. Rubbing with a soaked cloth will remove them
physically as well. You might also contact a certified pest control
company to see if there is a legal systemic that the company could apply
after working hours on a Friday. There is a restricted version of Metasystox
R (A.I. Oxydemeton) that has been used in the states for controlling
scale infestations on houseplants. This would minimize the danger to
office personnel. Keep in mind that one treatment will get most of them
but not all. Follow up treatments will be necessary for complete eradication.
Also, the dead scales don't fall off, since they have literally cemented
themselves in place. Their home becomes their casket!
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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