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November
9, 2006
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I have geraniums
planted in pots, but they look gangly and spindly. Can I trim the plants
at this time? How much should I trim so the plants fill in better? (Moorhead,
Minn.)
A: Trim the geraniums
so there are stubs 3 inches to 4 inches in length. I don't suggest growing
them during our dark winter months unless you invest in some good plant
lights. I would store them in a dark, cool location. Shake the soil
off the roots and dust them with sulfur. Bring the plants out at the
end of February and locate them in as sunny a window as possible. Use
supplemental lighting if necessary.
Q: A man called asking
if he could prune his bonsai spruce tree. He brings it in during the fall
and sets it out in the summer. Everything he has read says to prune the
tree in the spring, but can he do it now? (e-mail reference)
A: The reason for
pruning in the spring is the cuts will heal from the stimulation of
new growth. That wouldn't happen if the plant was trimmed now. If he
has to do it now, he is increasing the risk of stunting or injuring
the plant because the plant lacks healing energy.
Q: I started growing
four blueberry bushes. Two are growing like wildfire, but two died. I
did nothing to the soil and only gave the bushes water. I didn’t
realize until recently that the bushes had special needs. My local gardening
store told me to use Miracid, but I’m not sure if I should. I have
four more bushes to plant, but I am scared to plant them. I have the bushes
in pots and have them in the house, but they won’t last that way.
Another gentleman digs a hole a foot deep and a couple of feet wide and
then fills the hole with a mixture of soil and peat. I don't know what
ratio of soil to peat he uses other than it appears to be mostly peat.
He top-dresses new bushes with sulfur to counteract the surrounding native
soil’s tendency to raise the pH level. Every year after that, he
places sulfur around the base of the bushes. Is this the best way to plant
the bushes? (Pipestone, Minn.)
A: The practice
the gentleman uses is the most surefire way to success.
Q: Are blackie and
margarite sweet potatoes edible? I harvested some nice ones when I pulled
out my vines. I appreciate all your columns on horticulture. (e-mail reference)
A: Thank you for
the compliment on the column! As far as edibility, I don't know. I know
the potatoes are not toxic, but they may not have the flavor you desire.
Give them a try and let me know.
Q: My sister in Michigan
gave me a giant allium bulb for my birthday. I planted the bulb approximately
6 inches deep on the south side of my house. After a few days, I decided
to build a chicken wire cage around it to prevent small animals from digging
it up. As an added precaution, I filled the cage with leaves. The leaves
are firmly packed. What is your advice on this matter? If I need to change
something, I’d like do it before things freeze. I don’t want
to lose this bulb because it was a gift from my sister. (Fargo, N.D.)
A: Your actions
are OK. Everything should be in place for successful survival and growth.
Q: We have three large
poplars in our yard that are causing problems. The roots are shallow and
even growing aboveground. They are difficult to mow around and I'm concerned
about people tripping on the roots. What are my options for dealing with
the roots? I enjoy your column and have learned a lot. (e-mail reference)
A: You don’t
have a lot of options. You could build a large bed around the surface
roots and plant the area with shallow herbaceous plants. Another option
is to cut the trees down. The temptation is to cut out the roots or
cover them with topsoil, which many people do. Some get away with it.
In many cases, the soil over the roots eventually will lead to a decline
in the tree or death. Removing the roots puts the tree at greater risk
of toppling during a strong wind. Thanks for the very nice comment about
the column!
Q: My Christmas cactus
is starting to get flower buds. I'm keeping it in a cool, dark place for
longer hours and have limited my watering. I was told that now is a good
time to fertilize. Is this true and what do you recommend I use for a
fertilizer? (e-mail reference)
A: This is the time
to apply a liquid fertilizer with a 1-1-1 ratio, such as 10-10-10. Fertilize
again in February. Keep the watering to a minimum. Allow the top inch
to dry completely.
Q: I have a caragana
hedge that I cut down two years ago, but stumps keep shooting out. I treated
the new shoots with Roundup and even burned them with a torch, but they
still keep shooting out. How can I kill the darn things and destroy the
root system? (e-mail reference)
A: If you keep doing
what you are doing, you will win the battle. However, if you can get
your hands on a backhoe, the best approach is to dig the roots out.
Q: Should I cut my
asters this fall or should I wait until spring? Also, should we cut our
lawn short or should it be left long for the winter? (Sioux Falls, S.D.)
A: Cutting asters
or other perennials back is a matter of choice. Some like to have the
stalks remain through the winter to help trap snow for better moisture
and winter interest. Others want a clean, snow-swept landscape. As for
the lawn, drop the mower down a notch for the final mowing and collect
the clippings.
Q: We have a huge
silver maple and a smaller silver maple in our front yard. Every year
they seem to follow the cycle of the leaves turning yellow and then falling
off. This year, as of Oct. 24, the leaves are still green, but are shriveling
and falling off. Why didn’t they turn yellow this year? Is this
something we should be concerned about? (Minneapolis, Minn.)
A: You have nothing
to be concerned about and there is nothing you can do about it. This
is just the tree's way of saying that it isn't completely ready for
winter. The closing-down process of deciduous trees begins in late summer
or early fall with the shortening of sunlight. The weather progresses
to cooler nights and bright, clear, dry days. Chlorophyll production
is then slowed or ceases and gives us the yellows, reds and oranges
we all like. When Mother Nature throws a wrench into this mix through
warm nights and cloudy, rainy days, the whole process is thrown out
of kilter and the plants are unable to shut down gradually and completely.
What then happens is the leaf tissue is killed by the low temperatures,
so the leaves fall off or are blown off by the autumn winds.
Q: I've had a few
clients ask me about seeding lawns, especially dormant seeding. In one
of your bulletins, it recommends that dormant seeding be done at the end
of October. Is it OK to recommend that they seed now since we’ve
had 50-degree weather? The soil temperature is about 36 degrees. Is that
low enough to prevent germination? I've also had a question about navigator
lawn seed. Is navigator a fine fescue? Is it a low-maintenance grass that
would be good for use as a country lawn? Is navigator only available in
Fargo? (Bismarck, N.D.)
A: Now would be
a good time for dormant seeding because the temperatures for the rest
of the year will not be consistent enough to stimulate germination.
Fall seeding is encouraged over spring seeding because the seed will
not have to compete with weeds. Also, the grass seed that is applied
now will go through a priming process that begins the germination process
so that emergence next spring can keep up with the sprouting weeds.
Springtime brings on a flush of weed growth that spring-sown grass has
a difficult time keeping up with, which leads to lots of frustration.
It can be done, but consumers will bury you with complaining phone calls
about all the weeds. Many will suspect that the grass seed is the source,
which it isn't! Navigator creeping red fescue is a good lawn grass just
about anywhere except on a putting green or football field. It is available
from Agassiz Seeds in West Fargo. I don’t know if there is a distributor
in Bismarck. Navigator doesn't have to be used just because it is the
newest fine fescue on the market. Others are Ruby, Cindy and Dawson.
Any one of these would make an excellent low-input turfgrass system.
Q: I have two autumn
blaze red maples in my yard. The first year, the leaves turned a glowing,
fire red, which was beautiful. Since then, the leaves have turned from
green to brown. I don't know what to do. During the summer months, the
trees get full, dark green leaves. Do I need to use a special fertilizer?
(e-mail reference)
A: You know the
tree has the genetic potential to turn the colors you like because you’ve
seen it. Fall color on a tree is dependent on many factors, such as
shortening days, temperature variations and clear, crisp, sunny days.
Couple this with a little water stress and you should get your colors.
Beautiful fall leaves sometimes fail to show up on turf-planted sites
because the lawn receives a nitrogen fertilizer three or more times
a year, so there is no nutrient stress on the trees. If the tree is
getting water through a lawn sprinkler system, you may not get the beautiful
colors because the tree is not water-stressed. If the fall is warm,
cloudy and rainy, you will get no or very poor fall colors. In other
words, normal environmental stresses will produce the best fall colors!
Q: Our neighbor gave
us some black walnuts. He said all we had to do was put them in the ground
and they'd produce a tree. This sounds too easy. Any thoughts on how to
handle these nuts? (Turtle Lake, N.D.)
A: Your neighbor
is correct. If you wish, you can break and peel off the husk and plant
the walnut inside. That is too much work, though. Also, the stain you
will get on your hands will last longer than black latex paint! Actually,
the decaying husk on the nut helps soften the hard shell inside. Planting
them now provides the necessary stratification for germination.
Q: I have a spider
plant that is bursting out of its pot. I can't even water it. The water
I try to pour in immediately overflows. I have read that you should divide
a spider plant in the spring. Can I divide it now or will it be too harmful
to the plant? Do I cut the whole plant in half? Sorry, I'm new at this!
(e-mail reference)
A: You can do it
now. Some like to do it in the spring because of the increased sunlight
to stimulate regrowth. Cut the plant in half, thirds or quarters. If
your plant is anything like ours, it will be OK.
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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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