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July
15, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I have two older,
very tall lilacs planted close together. One has many leaves and blooms
while the other has a lot of blooms but the leaves are not as full. What
do you suggest? (e-mail reference)
A: Some rejuvenation
pruning right after they are done flowering. Cut about a third of all
the older canes back as close to the ground as possible. The plant will
send up a flush of leafy growth that should bud this summer and look
better next year. Repeat the process every year until you have pruned
all the older canes.
Q: I have seen apples
that are red on the inside, but I cannot recall their name. Do you know?
(e-mail reference)
A: Rome, pink pearl,
surprise and alamata are some examples. There are probably more that
I can’t recall.
Q: I put a few of
my spiderettes in water so the roots would grow. How long should the roots
be before I plant them? Also, I have some organic soil with a tiny bit
of pearlite in it. Is pearlite bad for the plants? What type of pots do
you suggest I use? (e-mail reference)
A: The roots should
be long enough to support the plantlet, a minimum of two inches. Perlite
will not hurt the plant, and since you are probably going to be hanging
these plants, go for a lightweight container with a saucer that is detachable
so you can pour off excess water.
Q: Can you tell me
how to harvest lilac seeds? I live in Canada and we have several hundred
planted in our yard. Many are transplants from a single bush that my deceased
grandmother had growing in her yard. This lilac variety has double flowers
that are deep purple and are just starting to bloom. (e-mail reference)
A: Allow the seeds
to dry on the plant, then harvest and spread on a table covered with
newsprint. Select the largest seeds and plant them no more than two
inches deep.
Q: I have a tree in
my yard that has new leaves, but they are starting to fall off. The leaves
do not seem to have any type of bug or fungus. I believe the tree is some
type of Maple. This also happened last year. (e-mail reference)
A: The problem could
be caused by a fluctuation in soil moisture levels. If the tree is important
to you, I would suggest getting in touch with an International Society
of Arboriculture certified arborist to find out what the problem is.
Often during dry spells trees will drop leaves as a means of conserving
moisture. Trees may also drop leaves after a dry period is broken by
rain or an irrigation event.
Q: My goldfish plant
has developed white, cottony looking spots on it. Do I have a fungus?
Would spraying with water/dish soap solve the problem? (e-mail reference)
A: It could be a
fungus, but I am willing to bet that it is cottony cushion scale at
the leaf junctions. If that is the case, insecticidal soap would be
somewhat ineffective. For a small number of these pests, I suggest taking
a cotton swab and dipping it in rubbing alcohol and rubbing them off.
The alcohol will dehydrate the pests, but not hurt the plant.
Q: I have a three-year-old
silver maple tree. The first two years it leafed green, but this year
all the leaves are rust colored. The only green is on the underside veins.
Any ideas? (e-mail reference)
A: I'm betting that
what you are calling rust is really an erineum gall mite infestation.
The surface of the leaf has a velvet-like texture or a patchy felt appearance.
It is nothing to worry about because it will not harm the tree. There
is nothing you can do about it. They will likely have a two or three
year cycle and then disappear for awhile.
Q: I have several
large peony plants. They are all blooming, but one spread out on the ground
instead of standing up. What’s wrong? (e-mail reference)
A: I have no idea.
Take a sample to a local nursery to find out what is going on. I don't
have enough information to make a judgment, sorry!
Q: I have some long-needled
pine trees that are 20 or more years old. I'd like to trim the bottom
branches to four feet above the ground so it would be easier to mow around
them. Will it hurt the trees? Is there a better time of the year to prune
them? (e-mail reference)
A: It won't hurt
them, so go ahead and prune them back to the trunk.
Q: I recently planted
hollyhocks in my flower garden. Should I cut them down after they have
bloomed or just leave them alone? (e-mail reference)
A: I wouldn't cut
them until the foliage begins to be a detriment to the quality of your
garden setting. I would cut back the spent flower stalks to the highest
leaves so they don't put energy into making seed.
Q: Can I transplant
a fern peony now if I take a good sized root ball with the entire plant?
We want to take a prized fern peony with us to a different residence.
(e-mail reference)
A: Give it a try
is all I can say. Water the plant 24 hours before digging it up and
protect it from exposure as much as possible. Plant at the same depth,
water and fertilize.
Q: I recently decided
I would like to move some spruce trees in a shelter belt to another area.
They are six to eight feet tall. Is it too late in the season to have
a tree mover do it? (Barney, N.D.)
A: I would suggest
waiting until early September to move them. That way, you will still
have root activity that will help establish the trees without any competition
from the top growth.
Q: When is the best
time to move or divide asparagus? (Forman, N.D.)
A: A lot depends
on the weather and soil. The best time is early spring. If you can’t
do it then, fall is perfectly acceptable. This is a very hardy perennial
and shouldn’t have problems either way.
Q: I have a question
that I'm sure you'll find easy to answer. I found some galls on a bunch
of rose bushes. They have tiny holes in them, which I assume are insect
holes. I hope removing them was the right thing to do. (Bowman, N.D.)
A: You are correct!
This is a gall caused by the larval stage of a small wasp. Removing
them was the right thing to do. Galls act as a nutrient sink and can
pull sufficient levels of nutrients away from the plant to cause deficiency
problems. There are no insecticides that can control them, so removing
them is the only solution.
Q: I am considering
harvesting tulip pod seeds. Should I let the pods dry and crack them open
or do you break into the moist, fresh pod? When do you plant the seeds
and what's this stuff about storing them in a refrigerator for 90 days?
(e-mail reference)
A: Allow the pods
to dry on the plant. Carefully harvest the pods and break them open
on a table or counter covered with white butcher paper (or something
similar). This winter, let them go through the cold period naturally.
You can push them by storing the seeds in the crisper of your refrigerator
for about 90 days, then sowing them. When planting, barely cover them
and keep them moist, not soggy.
Q: I read recently
that the product Florel (Ethephon) reduces cottonwood tree cotton production.
The trees in our yard and those of our neighbor’s produce lots of
cotton for about four weeks. (e-mail reference)
A: Yes, Florel will
reduce seed production (cotton). You will likely have to hire a professional
arborist to do the job, but it may be worth it to keep from being buried
in cotton every spring. Regional timing is important, hence the recommendation
for the arborist, plus they have the necessary equipment to adequately
cover the trees.
Q: Jade plants get
that lovely cottony bug which is easily killed by rubbing alcohol. Unfortunately,
Jade plants are one of the few plants that cannot survive the alcohol
treatment. I don’t know if the plant would even survive a Q-tip
dipped in alcohol treatment. I sprayed mine with a 50-50 water and alcohol
solution and the plant fell apart and died within a week. (e-mail reference)
A: Wow! Thanks for
the information. It will definitely be passed on to the readers. Glad
to know about their sensitivity to alcohol.
Q: I am getting a
new lamb. Her pen will be along the side of my flower bed that has hollyhocks.
Will they be harmful to her? (e-mail reference)
A: They are not
listed as being poisonous in either one of my reference texts. That
doesn't mean they will not cause digestive upsets if they are consumed.
Remember babies have more sensitive stomachs than adults.
Q: I recently bought
a hanging basket with petunias in it. The plant looked wonderful when
I bought it, but now it has turned brown and brittle, almost like it hasn't
been watered enough. I started to prune the dead areas and noticed a ton
of black little balls all over the plant. They come off pretty easily
so I thought maybe they were aphids, but I can't find a direct answer
on any Web site. What should I do? (e-mail reference)
A: Dump the plant
and get another one. What you are seeing are the spores of a fungus
disease that killed the plant. It is not your fault, just something
that happens. When I say dump it, I mean in the trash. Don't put the
soil in your garden.
Q: I just picked a
large amount of rhubarb from a friend’s patch. Are the leaves toxic
to animals? Our chickens love green clippings but I do not want to poison
them. (e-mail reference)
A: Good thing you
asked! Rhubarb is toxic to humans and I would think it would not be
too good for chickens either. I would relegate the leaves to the compost
pile if you have one.
Q: A couple of days
ago my husband pruned, actually sawed off, two large branches from a flowering
crab. Is there something we should put on the cut to protect the tree?
(Mandan, N.D.)
A: If the tree is
healthy and the cut was done properly, the wound will heal normally.
If the tree is not healthy and the cut was done improperly, then all
the dressing in the world won’t make a difference.
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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