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November
2, 2006
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I know a couple
who purchased some beautiful mums, but they are wondering what they should
do with the plants. Should they plant them or overwinter them in their
pots and plant them next spring? I suggested that they set the plants
outside for now and then bring them into an unheated garage for overwintering.
If they can plant the mums, what should they do to ensure the plant’s
survival during the winter? (e-mail reference)
A: Planted indoors
or out, there are no guarantees the plants will survival. Right now,
they would be better off planting the mums outside and watering them
in. Mulch the crowns with straw after the first freeze.
Q: A lady just called
to find out how to care for her white hydrangeas during the winter. Would
she take care of it the same as her endless summer hydrangea? (Lakota,
N.D.)
A: Yes, the white
Annabelles are tougher.
Q: I have a Black
Hills spruce that is loaded with cones, but a third of the needles have
turned reddish brown. There are 12 other Black Hills and Colorado blues
in this cluster. I'm considering cutting the tree down to prevent the
disease from spreading to my other trees. Can you tell me what disease
I'm dealing with? Is there a systemic cure for this condition or do I
need to remove the tree? I could easily remove it because it sits at the
periphery of the tree group. (Bismarck, N.D.)
A: Based on what
you have told me, I doubt this is a biotic disease. It’s probably
a reaction to environmental extremes from this past summer. It’s
a common problem around the state this fall. Based on the samples our
lab has received thus far, there is no evidence of a pathogen causing
the problem. The absence of a pathogenic disease does not remove the
threat of the continued decline and eventual death of the tree. The
heavy cone set you mentioned is symptomatic of a tree that is about
to die. You might feel better taking the tree down at this point.
Q: Do apple seeds
need any special conditioning, such as a cold treatment, prior to planting?
Also, is chelone lyonii (turtle head) supposed to die to the ground? (Mt.
Vernon, S.D.)
A: Plant the seeds
now and see what happens next spring. They do need a cold treatment,
which South Dakota winters will more than adequately provide. I would
assume they would die back with the arrival of hard frosts and cold
weather, and regrow the following spring.
Q: I called you a
few weeks ago to ask about a florist rose that had leaf sprouts on the
stem. You said to make cuts, put rooting hormone at the end and stick
them in damp sand. I have some chicken grit and perlite. Can I use one
of those instead? Also, is now an OK time to trim some lilac branches
or is early spring better? (Dickinson, N.D.)
A: Chicken grit
or perlite will work, but you need to have well-aerated and moist support.
Lilacs should be pruned in the spring right after blooming.
Q: After our purple
coneflower bloomed, green growth began coming out on the remaining uncut
cones. It looks as if little, green plants are growing on the cones. What
is this? (e-mail reference)
A: These are seedlings
coming up in the cones that didn't get expelled from the cone. Don't
worry, most will survive after they fall to the ground. This is a very
self-perpetuating species.
If you want, you could help them by trying to shake them loose and popping
them into the soil.
Q: I'm wondering about
the texture of woodarz apples. I like apples with a crisp, somewhat hard
texture, such as honeycrisp, sweet sixteen or zestar. (e-mail reference)
A: I assure you
woodarz is a crisp, hardy apple and one of the best for winter storage.
Q: I was searching
for an answer about my cactus plant. Someone gave it to me last year.
It was about an inch tall. It has grown to a height of 3 inches and it
has eight little baby plants. Should I remove the baby plants or leave
them alone? (e-mail reference)
A: If you enjoy
the cluster, let them stay for now. If not, then transplant them. At
some point, you will have to do so to allow them to develop normally.
Q: Are the leaves
of a ficus tree poisonous? I have three cats and a dog, so I am concerned
that the leaves are not good for them. (e-mail reference)
A: It is not considered
a poisonous plant. However, I still would discourage your pets from
eating the leaves because they are probably not good for your pets!
Q: I have a crab apple
that I want to move to the other side of our house. However, my husband
is concerned about the roots growing into the foundation. (e-mail reference)
A: Unless the foundation
is cracked and leaking, it should not be a problem. A lot of trees of
this and other species have been planted close to foundations without
causing a problem. With a roof overhang and better soil to mine outside
the overhang, the roots have little opportunity to move toward the house
because of soil, water and nutrient deficiencies. I suggest leaving
the tree where it is unless you have another reason for wanting to move
it.
Q: I planted ponderosa
pines this spring and was told to put sacks over them for the winter.
Should I do that? What can I do to get the most growth out of these trees?
(Fargo, N.D.)
A: The sacks are
not needed because ponderosa pines are native to our state and should
do fine unless they have been grown too softly (too much water and fertilizer).
Q: I recently emptied
my outdoor pots. To my surprise, I found that my chartreuse sweet potato
vines had produced huge tubers! This is the first time this has happened
to me. I’m thinking about dusting them, packing them in moss and
putting them in the cooler at 34 to 36 degrees. If they do survive until
next spring, how do I start new plants? Do you cut them up the same as
a regular potato? I appreciate the help! I always enjoy your column, too.
I was especially interested in the recent tree selection information.
(Mercer, N.D.)
A: Before placing
tubers in storage, they need to be cured for 10 days at 80 to 85 degrees
or between 65 and 70 degrees for two to three weeks. The tubers should
be covered to keep the humidity elevated. After curing, store the tubers
at 55 to 60 degrees. Chill injury will result if the temperature is
below 50 degrees. To keep the humidity high around the tubers, they
should be covered with or put in a burlap sack that is moistened periodically.
This is entirely different from the way white potatoes are stored. As
for planting sweet potatoes, that is entirely different as well. You
need to place them in hot beds about a month before the temperatures
stay above 60 degrees at night. Cover the potatoes with damp sand and
keep the beds at 75 to 80 degrees. This will cause slips to form, which
are then removed and planted. I'm glad that you are a faithful reader
and that the information is useful to you. Thank you!
Q: I have been reading
your columns, but I do not understand any of the horticulture lingo, so
I’m hoping you might give me some simple answers. How do I prune
and where do I cut a jade that is leaning heavily? Do I cut into the trunks?
How do I grow the cut pieces and how many can I remove? Will it work if
I put the cut pieces in water? Also, I would appreciate any advice on
how to encourage my jade to flower. How do I get a white jade plant? (e-mail
reference)
A: One of the most
difficult, if not impossible, tasks is to communicate through words
alone how to prune a plant that one cannot see. Your questions are valid,
so I will attempt to be as clear as possible in answering them. Anytime
you cut into a plant, it will fare better with the smallest cut possible.
It’s the same as undergoing an operation. You can cut into the
trunk or any of the branches, but never leave a stub. Always cut back
to a lateral branch or just above where a leaf comes out of the stem.
Generally, the recommendation is to not remove more than 25 percent
to 30 percent of the leaf tissue at a time because doing so will reduce
the food-making capacity of the plant too much. Propagation is possible
by planting the cuttings in water, but I don't recommend it. I prefer
sand alone or a sand and peat mix of equal proportions. For details
on propagation techniques, go to www.ag.ndsu.edu/pubs/plantsci/landscap/h1257.pdf.
Also, jade plants will flower when they are ready. Jades are sold as
foliage plants, not flowering plants. Flowering is a rare occurrence
to be enjoyed if and when it happens. Flowering is not something you
or I can manipulate the same as on an apple tree or a lilac. I never
have heard of or seen a white jade. Hope this helps.
Q: I have a maple
tree that was damaged while my house was built. However, after seven years,
it is still alive. Earlier this year, I noticed sawdust on the ground
on one side of the tree. I looked closer and noticed holes bored into
the tree. Shortly after, I noticed black ants climbing up the tree and
going into the holes. I’m afraid the ants will weaken the tree and
potentially make it dangerous during a storm. Is there something I can
do to eliminate the ants? (e-mail reference)
A: I really doubt
the ants are doing direct damage to your tree. What is more likely,
they are harvesting larval borers that are tunneling under the bark
or insect eggs that may have been laid inside the tree. To protect the
tree from further borer damage, I would suggest an application of Merit
insecticide. It is sold under the commercial name of Bayer Advanced
Tree and Shrub Insect Control. It is taken up systemically through the
roots and then is available to eliminate any plant-feeding insect for
up to 12 months.
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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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