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May
11, 2006
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I want to seed
new grass this year because weeds have overtaken my lawn. When should
I start, how should I cover the seed and what is a good, hardy grass?
I have two small boys who will be driving their toys over the grass once
it grows. (Beach, N.D.)
A: If you have active
children who will use the lawn, you might want to consider the "athletic
field mix," or what is sometimes called "playground mix."
These are mixtures of 50/50 perennial ryegrass and Kentucky bluegrass.
Any grass seed will require regular watering to get it established and
maintained. It also will require a regular maintenance program of at
least annual fertilization and consistent mowing to look good and withstand
the stress of traffic.
Q: A homeowner has
roots from his blue spruce invading his garden. What is the best treatment
for this problem other than taking out the trees or moving his garden?
(e-mail reference)
A: Well, without
the obvious choices, the only other solution is a root barrier. The
roots have to be cut back and a barrier installed. This barrier can
be a strip of plastic edging, treated lumber or a material called Biobarrier.
Q: I have someone
in my office who has some shrubs that have had the bark eaten off by rabbits.
The bark has been eaten off from the ground up about 8 inches. Will the
shrubs die? (Ellendale, N.D.)
A: If the bark has
been completely removed around the stems, the wood above that point
is dead. The shrubs often will send out a flush of new growth as they
would if they were cut back heavily, so don't dig them out just yet.
Cut off the damaged stems to the crown and see what happens.
Q: I had three of
my river birch trees trimmed on April 1. Now the trees are bleeding a
lot of sap. I was reading on your Web site that birches should be trimmed
only when the leaves are out. I thought the professional tree trimmers
we hired should have known this. Will our trees die? The sap also is bleeding
on some of my perennial plants. Will the sap kill the plants? At this
point, what should we do to save the trees? If the trees’ health
is at risk, is the tree trimmer we hired liable for damages? Before he
trimmed the trees, I asked him repeatedly if it was OK to trim them at
this time of year. He said the trees would be fine! He also trimmed some
maple, oak and elm trees for us at the same time. I hope all our trees
are OK!
(Bloomington, Minn.)
A: Your trees will
be fine. The reason for the delay in pruning bleeders, such as birch
and maples, is for the very reason of your concern. Unlike humans, trees
will not bleed to death. From a disease standpoint, pruning while they
are dormant is a better choice. I have a huge birch in my front yard.
I have a professional prune it every summer with no disease consequences
or sap flow. The only way your tree trimmer failed you was about not
informing you of the sap flow this time of year. That is not a crime
on his part, just an oversight. Relax and stop worrying.
Q: I have a row of
arborvitae approximately 12 to 15 feet tall. My dogs chewed-off the bottom
growth on several trees two years ago. I have since fenced off the trees
and started nursing them with tree food. The trees are still alive, but
look sickly and have produced no new growth. Is there anything I can do
to bring them back to their original strength and stature? (e-mail reference)
A: If the dogs chewed
off all the green foliage at that level, then nothing will grow back
at that height. The trees should survive because of their size, but
the chewed off stubs will remain just that. Sorry! Fertilizer will not
restore the trees, so save your money.
Q: Is a goldfish plant
toxic? (e-mail reference)
A: I don't have
it listed as being toxic, but I wouldn’t nibble on it to find
out.
Q: What's the best
way to get rid of box elder trees on conservation reserve program land?
(e-mail reference)
A: Other than ripping
out the box elders, allow them to leaf out this spring and then cut
them back to the ground. The leafing out will spend the carbohydrate
reserves from last fall, so the trees will be too weak to releaf to
any great extent. Whatever does pop up again can be nuked with Roundup.
Q: Can hosta plants
be planted in a large pot or planter as opposed to the ground? (e-mail
reference)
A: Yes!
Q: Should I fill the
holes left after lawn aeration? We’ll be aerating our lawn and thatching
it. I’d like to leave the holes empty, but my husband wants to fill
them with sand. Please help with this dispute. (Bismarck, N.D.)
A: As usual, the
wife is right. Leave the holes. They eventually will close, but leave
a more open, porous soil. The grass will respond beautifully to the
treatment. What some folks do is core aerate in the morning, allow the
plugs to dry in the sun, then pulverize them with a power rake, which
acts as a top-dressing. What your husband probably has seen is the use
of this practice on golf courses. The greens are areated, the cores
removed and then the green is top-dressed with selected sand. It works
on golf courses, but not home lawns.
Q: My mom has some
tulips, but she doesn't know what to do with the dead buds. (e-mail reference)
A: All she has to
do is snip off the flower stem when the flowers begin to fade. She even
can leave the flowers on without damaging the plants. However, most
homeowners are not interested in tulips setting seeds, so removing the
flower stems saves the energy of making seed. That energy can be stored
in the bulb for next year's bloom.
Q: I bought two weeping
pussy willow trees (salix caprea pendula). Will I have any luck growing
them here in Hazen? I also would like information on their care in the
summer and winter and how to grow them on my own. (e-mail reference)
A: These are not
the true pussy willows that like continuously moist conditions. They
will do well in a drier location. The trees are marginally hardy for
your area. In fact, I'll be surprised if they make it through a typical
Hazen winter unless you provide ample protection before everything freezes
up.
Q: I’m a third-generation
fruit grower. I grow a lot of pink lady apples. Normally in Western Australia,
we start picking the apples about the first week of May. There is one
grower who starts picking about the first or second week of April. I’ve
spoken to many other growers and no one knows what he is doing to be able
to pick so early. Obviously, he is spraying the trees with something or
giving them some fertilizer so the apples ripen earlier. He makes huge
money because he finishes before anyone else starts picking apples. Do
you have any ideas on what he may be doing? (e-mail reference)
A: He is probably
using Alar, a chemical that accelerates ripening and fruit coloration.
It has been banned for use in the U.S. since 1989 because of a probable
increase in the incidence of cancer. If you have a regulating agency
in Australia, you might ask the agency to check into what he is using.
If it is illegal, it needs to stop or at least his shipments to America
should cease. The pink lady is a popular apple over here, but we don't
need apples that may have been treated with a potential carcinogen.
Q: Can you recommend
a bush for the north side of a house that would get 4 to 5 feet tall?
How about the south side of the house? (LaMoure, N.D.)
A: By saying "bush,"
I am assuming you mean something that is deciduous and not an evergreen.
North-side selections
would include hydrangea (Annabelle), Northern Lights azalea (with major
soil modification using sphagnum peat moss), currants and sumacs. South-side
selections include Russian almond, any number of dogwood shrubs, dwarf
honeysuckle (Lonicera tatarica, Nana, and Arnold), dwarf lilacs (Miss
Kim) and dwarf winged euonymus (can actually go either location, but
you will get the best color in the fall if planted on the south side).
Q: Is now the best
time to spray for crabgrass? I've seen some coming up in the lawn. Also,
is Ortho Weed-B-Gone for crabgrass any good? What product would you recommend
and where can you get it? (Fargo, N.D.)
A: Right now is
perfect timing for Fargo because the forsythia are finishing their blooming,
but the lilacs haven't started. The product you mentioned should do
a job fine job, but you need to follow the label directions. Keep in
mind that crabgrass germination is not a track meet. Crabgrass germination
takes place during the entire summer. Follow your spraying with a lawn
fertilizer application, mow high (3 inches) and don't allow the lawn
to go into drought conditions because that will encourage crabgrass
growth.
Q: Something is happening
to the lawn in our backyard! Large patches of what should be green grass
are getting more yellow by the day. The largest area is under an apple
tree and other smaller patches are in various other spots. Some yellow
spots are near a bird feeder and another tree! We have fed small birds
in our backyard for several winters, but this yellowing has never happened
before. What do we need to do to bring our grass back to normal? (Enderlin,
N.D.)
A: It is hard to
say what the problem is without a lab diagnosis. I would suggest fertilizing
and doing a little reseeding in an attempt to thicken things up. It
also may be damage done from the birds, if you have been feeding them
in this area for many years, but that is just a guess. Try the fertilizer
and reseeding to see if that improves things. If that doesn’t
help, take a sample and send it to the plant diagnostic lab at NDSU
for analysis of possible disease or insect problems.
Q: I just purchased
a historic home loaded with French tulips. We moved in last October. This
spring, we had hundreds of beautiful, colorful tulips. I am wondering
how long these tulips will live. I would love them to last 10 years, but
I was told two to three years. I don't know how long they have been planted
here. I suspect for more than three years because the house sat vacant
for a year before we took possession. (e-mail reference)
A: I think someone
gave you some wrong information or you got it confused. Tulips will
last much longer than two to three years, but they often need to be
dug up and spaced every three to five years to maintain their blooming
vigor. I would suggest that, this fall, you dig them up and reset them
with more spacing and possibly in some new locations.
Q: I planted a lot
of gerbera daisies last year. They are in full sun almost all day and
did extremely well. They were beautiful. I thought they were perennials
and treated them as such. I cut them back in the fall after they stopped
blooming. I haven’t seen anything leading me to believe that they
are coming back this year. Is it too early to be seeing any signs of life
from them or did I kill them? I am extremely distressed. I am trying really
hard to create perennial gardens throughout my yard because of the time
involved with planting annuals each year. Any advice or information you
can pass on would be great! (e-mail reference)
A: Don't get stressed
out because it isn't worth it. The gerbera daisy is an annual, so unless
they had a chance to drop seed, you probably will not see anything come
up again. Go to my Web site at www.ext.nodak.edu/extpubs/plantsci/landscap/h322.pdf
for a list of annual and perennial flowers.
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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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