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September
15, 2005
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: This spring I
noticed a wildflower growing in a friend’s pasture. We haven’t
seen this plant before. It’s a low-growing plant that has fern-type
leaves and dark purple blossoms. I have been told it’s a wild licorice
plant. I have seen it growing along the ditches in the area. Will it harm
the integrity of the pasture the way leafy spurge does or is it just a
nice wildflower? Will the cattle eat this plant? If it is a plant that
needs to be controlled, what pesticide do you use to eradicate it? (e-mail
reference)
A: Wild licorice
is found throughout North Dakota, east to Minnesota, and northwest to
Washington and Alberta. It’s a perennial that forms tough, deep
taproots and interconnected root crowns. It is a legume, growing about
18 inches tall in North Dakota. Botanically, wild licorice is known
as Glycyrrhiza lepidota and commonly found in wetlands or coulee bottoms.
Grazing seems to have little effect on the density of this plant. It
is not listed as being poisonous to livestock. I would say it is invasive,
given the right conditions, so the fact that it got started in your
pasture would be a red flag to me that this species would be “happy”
to spread throughout your pasture! Get the plant out as soon as possible
by digging or with Roundup.
Q: The other night
I was looking over my plants and to my surprise, I saw a millipede in
my coleus plant. The little bugger was crawling around in the soil. Can
these critters harm my plants? Also, the soil that I use for all my plants
is from Miracle-Gro. I noticed that in some of the soil there are little
weeds. The weeds look like miniplants with two small leaves and a stem.
Could these be weeds? (e-mail reference)
A: The millipede
could have come from anywhere, including the potting soil. They feed
on decaying organic matter, which should be abundant in the potting
soil. If what you see coming up is not what you planted, then they are
weeds. You might want to check with the company where you made the purchase
and see if the staff have an explanation. Potting soil is supposed to
be pasteurized, which means no insects or weeds popping up! You might
take the pot with the weeds down to the store to show them, along with
the remaining contents of the bag to get a refund or replacement.
Q: What causes evergreen
tree needles to turn brown? It is especially bad on the south side. Is
this a lack of moisture or do they lack an element, such as iron? (Faulkton,
S.D.)
A: The browning
of evergreen needles is due to the loss of moisture from the winter
sun. The green color of the needles heats up beyond the ambient air
temperature and the frozen soil cannot send water through the root system.
The stomatal pores open, the moisture vapor leaves the needles and eventually
is depleted, and then the needles turn brown. Often the buds are not
adversely affected and the plants will regreen on the browned side.
This problem is common on young trees, especially if they were planted
recently. It can be prevented by spraying the foliage with an anti-desiccant,
such as Wilt-Pruf, prior to winter’s arrival and again in late
winter during a thaw when the temperature is above 40 degrees.
Q: We have a row of
lilacs that we are taking out. I have noticed that there are many red
ants around the base of the lilacs. Is this normal? (e-mail reference)
A: Red ants are
omnivorous, which means they eat flora and fauna in the environment.
Any nursery stock you bring home should be inspected carefully to be
sure that no red ant colonies are developing. Count yourself lucky if
you never have been stung by these aggressive predators! To get rid
of the ants (makes me itch just talking about them!) you will need to
use an insecticidal drench on the soil or mound. Insecticidal mound
drenches with common insecticides usually are effective against fire
ant colonies. The mound is flooded with a large volume of liquid containing
a contact insecticide, such as carbaryl, diazinon or dursban. Numerous
insecticides are labeled for this use. A major problem with this method
is that the queen is sometimes too deep within the colony to be contacted
by the toxicant. Care must be taken not to disturb the mound prior to
applying the drench. A disturbance will alert the colony and the queen
may be taken deeper into the mound. Insecticidal surface dusts or granules
have a limited effect on a colony if they are not watered in. The dissolved
granules must come into direct contact with the ants. As in mound drenches,
care must be taken not to disturb the colony prior to application. Take
care and good luck!
Q: We have been searching
the Internet to see if a Norfork pine can be topped off. Is this possible?
(e-mail reference)
A: You bet. The
best way to top it off is by air layering. That way you get another
plant to work with. Go to my Web site on home propagation techniques
for a complete description of the procedure. The address is
www.ext.nodak.edu/extpubs/plantsci/landscap/h1257w.htm.
Have fun!
Q: Could you please
help me with a problem? Last year I planted six midget arborvitae bushes.
They looked great for several months. Last fall I noticed the side of
one turning a rustlike color. Later that side became brittle and died.
This spring I noticed several other bushes with scattered areas of the
same thing. What can I do? I have heard about using Epsom salt. Please
help! (e-mail reference)
A: I don’t
know of a rust fungus that hits arborvitae. Cedar apple rust refers
to the “cedar” as being a juniper, not a thuja (arborvitae).
What your plants might have is juniper blight (Phomopsis blight). To
control it, prune out the infected branches and spray with a fungicide
such as Benomyl, Funginex or Cleary’s 3336. To apply the fungicide,
use a sticker-spreader.
Q: We grew three crabapple
trees from very small seedlings. One tree is now about 10 feet tall while
the other two are about 6 feet. This is the third year that they have
been in the ground, but we have had no blooms. The trees have not been
pruned, except to remove some suckers. Is the absence of blooms normal
or do we have to do something to promote blooms? (e-mail reference)
A: Hang in there
for a couple more years! In some cases, it takes about five to six years
for these trees to grow up enough to produce flowers.
Q: What is the tallest
hollyhock on record? Our hollyhock is now at 14 feet 6 inches. (Kingman,
Ariz.)
A: I have no idea
what the champion hollyhock is! Perhaps one of our readers will know.
If that happens, I’ll pass it on to you!
Q: We have two very
healthy bull pine shrubs. Can I start a new shrub from a branch or should
I wait for the cones to mature and then plant the seeds? (Rugby, N.D.)
A: Ponderosa pine
can be propagated using the cones (actually the seeds in the cone).
Place a bag over the female cones after fertilization has taken place
to keep the squirrels and birds away from them. Plant immediately after
they drop into the bag because they have no chilling dormancy requirement.
Q: I have a new greenhouse
that I am using to grow vegetable and annual seedlings. The seedlings
are good, but not as compact as I see in commercially grown six packs.
I have measured the light in the greenhouse and it is sufficient. I have
heat, so I can control the temperature. Is there a certain fertilizer
that I should be using to keep everything compact and increase the flowering?
Could it be that I am keeping them too moist? I would appreciate any advice
you could share with me. (e-mail reference)
A: It is likely
that you are growing them too warm, especially during the night hours.
High light intensity and warm days equals good growth, while cool nights
help keep everything compact. You also should be in the hardening off
stage now or should have been some two to three weeks ago. This is where
you gradually reduce the water and temperature to start exposing the
plants to the outside environment. This builds compact growth and prepares
the plants for the capricious weather that typifies our northern summers.
Q: Are there perennial
vegetables other than rhubarb and asparagus? If so, what are some other
perennial vegetables? (e-mail reference)
A: The common perennial
vegetables are rhubarb, chives, top multiplier onions, horseradish and
asparagus. Everything else is an annual or biennial.
Q: I recently took
a botany class and loved the experiments. Why do leaf cuttings take longer
to produce new leaves than stem cuttings? (e-mail reference)
A: Energy reserves,
more “horsepower” so to speak, to get production going at
a faster rate.
Q: I have a plum tree
that has been doing great since we planted it two years ago. The problem
is squirrels or birds (I haven’t seen the culprits) are eating the
fruit as soon as it starts to get soft. Do you have any suggestions? (e-mail
reference)
A: Most likely,
the problem is caused by birds. Squirrels steal the produce lock, stock
and barrel! You can use a few “tricks” to solve the problem.
Throw some bird netting over the tree after the fruit is set, but be
sure to secure it to the trunk or else the birds will go up inside the
net and get stuck there. Apparently they are not smart enough to figure
out how to get back out. Another trick is to hang some owl balloons
and aluminum foil around the tree. Finally, a motion sensor sprinkler
that can be situated around or in the tree may do the trick. Just remember
to turn it off before you approach the tree or you will be doused!
Q: I love plants and
am taking care of several at my workplace. Some are peace lilies and ivy.
I honestly don’t know what some are called. There is no color to
the plants. They just are green plants. A few are rather large. I recently
repotted some peace lilies and have them in a window so they get plenty
of sun, but they look droopy. I water them once a week. I will water them
with Miracle-Gro in the future. Would it be OK to use Miracle-Gro along
with Epsom salt or would that be too much fertilizer? I just want to help
the plants grow and look their best. (e-mail reference)
A: The most important
suggestion is to find the right balance of water for each plant. Droopy
leaves mean that there is not enough water being supplied, which is
a characteristic of peace lilies. Most other plants will get along fine
with a weekly watering and removing the excess water from the tray.
Don’t be too zealous with fertilizing. The plants will respond
best to fertilizer applications when they are actively growing. You
can try Epsom salts (magnesium sulfate) to see if the plants respond
better. Chances are the level of these two elements is adequate and
will not result in any visible response. If fertilizing with any material
on houseplants, be sure to use a diluted amount. Use about half of what
is recommended on the label because the requirements are varied with
each plant species and the pot size (volume of soil) also varies.
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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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