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July
29, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: Is there a way
I can grow honeycrisp apple trees from the seeds I get this fall? (e-mail
reference)
A: It is illegal
to propagate proprietary nursery stock. Have patience and stay legal,
the local nurseries should have them in stock next season.
Q: We planted an autumn
blaze maple last fall. It came in great this spring, but now the leaves
are turning brown-red, almost as if it was fall. Is this an iron deficiency
problem? What can I do to save this tree? (e-mail reference)
A: Check the planting
depth. The top of the rootball should be just under the soil.You might
have an International Society of Arboriculture certified arborist check
the tree to see if a more accurate diagnosis can be made.
Q: I have a spectablis
dicentra (bleeding heart) that I haven’t planted. I would like to
know how to split it or if splitting will hurt it. (e-mail reference)
A: Don't split it
now, just plant it. After it has been in the ground for three to five
years, dig it up and split it after it has finished blooming. Use a
sharp, straight-edge shovel or a large sharp knife.
Q: I have had my aloe
a little over a year. It seems to be doing well and getting very large.
Since last fall it has been getting white fuzzies on it that keep growing
and hanging down. They feel sticky. I keep washing them off, but they
keep forming. What are they and what can I do about it? (Bruce, S.D.)
A: It sounds like
the plant has an infestation of mealybugs or cottony cushion scale.
Make a solution of 50 percent rubbing alcohol in a pan large enough
for you to invert the aerial part of the plant into the solution for
about 10 seconds. Then let it air dry. That should take care of either
of these characters.
Q: I fertilized our
snow on the mountain plants. They are now growing straight up, getting
pods and seeding. Is this normal? (e-mail reference)
A: Going from a
ground cover plant to an upright is hardly normal. You want to keep
the seed pods from forming, so mow it down with the mower at its highest
setting. It will recover, going back to the prostrate habit it had.
Q: Could you tell
me why my red maple tree has round holes in some leaves? It has been in
my front yard for about six years. (e-mail reference)
A: It could be cutter
bees. The damage shouldn't be extensive and the bees don't hang around
for long. If the problem continues, to the point where it appears that
it may impair the health of the tree, look for the culprit and initiate
some kind of control once the offending insect has been identified.
Q: Last fall I had
a 70-foot cottonwood tree removed and its stump ground down. The stump
grinding did not take care of the many roots running through my yard.
This year I have shoots coming up all over my yard. I've tried cutting
them as well as spraying with Roundup, but it doesn't seem to have any
effect. I am hoping to re-landscape my yard and put down sod. Currently
this looks to be impossible. (e-mail reference)
A: Get a selective
shrub/brush killer at the local garden center. It should contain a compound
known as dicamba, which, when applied to the leaves coming up on the
suckers, will be translocated to the roots and kill them. Don't expect
that one application will solve the problem. A 70 foot cottonwood has
a very extensive root system. The roots have plenty of stored carbohydrates,
the safety net for the tree's survival. Plan on spending the summer
applying the compound, with your sod installed sometime in mid -September.
Make sure the material you use is not toxic to the turf and don't be
tempted to do revenge spraying by making the mixture stronger than is
indicated on the label. That will only burn the foliage back and not
be translocated.
Q: I have rhubarb
question for you. Is it possible to successfully plant the seed of rhubarb
plants? (Dickinson, N.D.)
A: It should work,
but I have never tried it. My references tell me the seeds should be
planted a month before the last frost. Plant the seeds two inches apart,
a half inch deep and hand firm the soil. Thin the seedlings so they
are a foot apart. It takes 90-100 days for the plants to mature. The
reference book says it is best if the seeded rhubarb is treated like
an annual crop, as the plants that are allowed to go into their second
year tend to bolt to seed stalks quickly. Plants that develop seed stalks
directly, as the new leaves grow, should be culled out. I would suggest,
for the sake of experimentation, the seed be placed in a refrigerator
crisper for about 30 days. Then go through the planting schedule to
see if the seeds germinate with that short a cold treatment. Leave some
seed behind for another 30 days. Hope this helps!
Q: Can lilacs and
Lombardy poplars be fertilized with Miracle-Gro if they were just planted?
Can Miracid be used on newly planted Colorado blue spruce trees? (Dickinson,
N.D.)
A: These products
are often used in getting plants established the first year. I have
used them for as long as I can remember and have never known them to
hurt any plant.
Q: A farm homeowner
has a serious problem with white grubs. They have been treating the lawn
with Sevin. Will the grub problem just continue if they don't treat every
acre of their farm yard? They have a large area to mow. (Cando, N.D.)
A: The typical lawn
grub goes through cycles. Believe it or not, the cycle depends on weather
and natural control forces such as disease, predatory insects, birds
and mammals. I would advise treating only the worst areas with Sevin.
Spray the entire area with a biological agent such as Bt for long range
control. Every lawn has some grub activity.
Q: What is the proper
way to store paper white bulbs during the summer and then replanting them
for forced blooms in the fall of the second year? I currently have them
in a paper bag in a cool dark place. (e-mail reference)
A: It sounds like
you are on the right track. Check them occasionally to see if any are
beginning to rot. Throw away those that are.
Q: I have a question
about a Marshall seedless ash tree. This spring the main stem of the tree
didn’t bud-out well. We thought it froze, but when I checked it,
the tree looks like it has holes worn in it. (Corsica S.D.)
A: The holes could
be caused by bark beetle or sap-sucker activity. From what you describe,
it sounds more likely to be the former, unless the holes girdle the
branch. If you can, locate a certified ISA arborist (check the yellow
pages) to see if the tree can be treated and saved.
Q: We just moved into
a new home and found out we have tulips. I have a few questions because
I don’t know much about them. Do they prefer full-sun or part-shade?
I would like to move them because I don’t like where they are planted.
When is the best time to transplant and what do I need to do to get them
ready? (e-mail reference)
A: Tulips will grow
well in full-sun or part-shade. The best time to transplant is in the
fall, after the Labor Day weekend. Be sure to tag where they are now
so you don't damage them when digging for them in the fall.
Q: Yesterday I purchased
a mum plant at our local greenhouse. It is in full bloom and has several
unopened flower buds. I would like it to also bloom in the fall, but the
greenhouse workers gave me conflicting advice. One said I should shear
off all the flowers and buds all summer if I want it to bloom this fall.
The other worker said I should deadhead it and the plant should bloom
all summer and fall. I hope it will come back every year, so I want to
give it a good start. (e-mail reference)
A: Mum flowering
is controlled by day length. Mums are genetically programmed to begin
blooming during the short days of late summer or fall. The greenhouse
operator likely limited light this spring to get them to set flower
buds and be marketable around Memorial Day. If you deadhead or cut it
back hard, it will not flower until sometime late this summer or fall,
depending on where you are located and what cultivar mum you are working
with.
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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