|
February
26, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: A gentlemen came
into the office with an apple tree problem. His dozen or so apple trees
(different varieties) lose their apples before they become ripe. The trees
are planted in different areas of his farm. Some are planted in shade
and some in direct sun but they all have been dropping their apples while
they are still green. Is there something he can do? (E-mail reference)
A: Have him spray
for apple maggots at blossom petal drop. I suggest he use Sevin, which
should be applied at least twice, seven days apart. After that, have
him purchase a few "mock apples" that will attract the female
adult who will become stuck on the false fruit and die, unable to lay
her eggs on the developing fruit. He should also pick up and destroy
fallen apples throughout the summer. The trees in the shade will likely
give him some additional problems later on.
Q: I know this might
sound stupid but when you say "mock apples" do you mean just
any old fake apple or is there something called mock apples that are made
for this purpose? I can't imagine why a maggot would get stuck on a plastic
apple! (McClusky, N.D.)
A: They do sell
apples, plastic or otherwise, that are covered with a tangle-foot type
of material. The apples may contain pheromone that attracts the female
adult insect. The insects die of dehydration after being trapped. You
can also get the sex pheromone traps that attract the males into thinking
there is a female within. It’s nasty to the insect but it works
and is better than spraying a lot of indiscriminate insecticides.
Q: We have a hibiscus
plant in a southeast bay window. It blooms very nicely but has problems
with white flies. We also have the same kind of plant in a back bedroom
on the northwest side of the house. It also blooms some but it doesn't
have any white flies. The temperature in the backroom is in the 60's.
Does the temperature keep the white flies from invading? (Brookings, S.D.)
A: It could be,
especially if it is in the lower 60's. You can try an old trick I used
a few years ago to get rid of white flies but you have to be careful.
Set the plant outdoors for no more than 20 minutes in sub-freezing weather
but be sure the top of the pot is wrapped in aluminum foil. Then bring
it back it and prune it back somewhat. The leaves will all be toasted
of course, but so will the white flies. The plant will eventually re-bud,
leaf-out and bloom again for you. It worked for me and I never had to
use an insecticide.
Q: I am thinking of
buying a young pussy willow. My concern is the effect the roots may have
on the rest of my small garden, especially my pond. (E-mail reference)
A: There are a couple
of plants that are referred to as pussy willow such as salix caprea,
also known as the goat willow, and the salix discolor, which is the
true pussy willow. You have reason to be concerned if you’re purchasing
a true pussy willow. They are very susceptible to cankers and require
almost continually moist soil in order to thrive. It is a poor addition
to your landscape but is fascinating when found in the wild.
Q: I noticed in this
week's edition of Hortiscope that someone from Napoleon asked about growing
pecans. I thought I remembered seeing a variety that was fairly hardy
in one of my catalogs. I did find it in the Miller's Nurseries catalog
out of Canadaigua, N.Y. It says this winter-hardy pecan will tolerate
30 below temperatures. It shows that the variety will grow in zones four
through nine. I have ordered fruit trees from this company and they have
good quality trees. (E-mail reference)
A: Go for it and
let me know what kind of results you have. It would be great if you
succeed because I'd love to see pecans growing in our region as a dependable
nut crop. Pecans are tasty and healthy.
Q: I was really interested
in your response to the question regarding a cat eating a spider plant.
I had this very same problem so I asked about it at the veterinary clinic
where I work. I had also previously noticed that my cat was very hyperactive
and would run around like a maniac. I found it very interesting when the
veterinarian told me that spider plants aren't poisonous to the cat, however,
spider plants are to cats the same as LSD is to humans. It sounded very
odd to me that my cat was getting high off of a plant. I followed their
advice and put the plant out of the cat's reach and now my cat is no longer
hyperactive and is actually quite pleasant. I just thought that he was
eating it out of boredom. Also, is it true that spider plants grow better
in clay pots? (E-mail reference)
A: Thanks for the
information. I'll check into it here to see what is going on with spider
plants and cats. All plants grow better in clay pots but plastic is
so convenient and easily maintained that the difference isn't important
except in contests.
Q: The oak tree by
our garage dropped almost no acorns last year. Usually it litters the
driveway. Does this have any significant meaning? I was pleased because
I didn't have the big mess to clean up but I'm wondering if it's a sign
the tree is unhealthy. (E-mail reference)
A: The acorns not
dropping is a sign that the tree spent too much energy the previous
year developing the fruit. The tree needs to build up its carbohydrate
reserves again by not bearing any fruit. In some cases it may take two
years. Enjoy the respite because the acorns will return.
Q: I am looking for
a crown of thorns like I once had. It had actual flowers (red) with five
or so petals, not just bracts like all the plants I find under this name.
It had longer branches, covered with smaller oval leaves and not as shrubby
shaped as those I see now. I am wondering if what I had was a related
plant or a variation. (E-mail reference)
A: I am afraid that
you must be thinking of something other than a crown of thorns (Euphorbia
milii). It’s possible the one you had was misnamed either accidentally
or intentionally. I'm sorry I can't help you more.
Q: I recently heard
a news report about North Dakota wineries perhaps not having enough grape
suppliers to satisfy the requirement for locally grown grapes. I have
been thinking about growing grapes for wine production. What type of grapes
would be best for my area? (Moffit, N.D.)
A: I suggest contacting
the wineries to see what varieties of grapes they want because there
are many varieties that have the potential. It’s better to grow
what the wineries want and have a reliable market source than to grow
something no one wants. Valiant is the hardiest variety available and
is being successfully grown in central Manitoba. However, it is probably
the one least wanted by the wine makers. Ask them anyway. Frontenac,
from the University of Minnesota, is a red wine grape, fairly disease
resistant, bears heavily and produces a wine that is medium bodied with
delightful plum and cherry flavors. It has high acid content that needs
to be dealt with in wine production. King of the North is from southern
Wisconsin. It is a heavy producer and yields a concord-type red wine,
which is very customer-friendly. Chontay is an old Hansen hybrid from
South Dakota. It has excellent hardiness, vigor and productivity. It
makes a dark wine, jelly or juice. White wine producing grapes are not
as numerous and hardy for the north, but here are a few to consider
anyway. Prairie Star has good vigor, bearing capacity and excellent
cold hardiness. It is often used in blending and produces a California
style white wine. Frontenac gris is a mutant (chimera) from the original
frontenac vine. It produces a nearly white wine but is culturally identical
to the original frontenac in every other way. La Crescent produces a
good white wine that has an apricot/pineapple flavor that is usually
favored as desert wine. The NDSU Department of Plant Sciences is in
the launching stage of grape-wine production research. We will be growing
these and other varieties from Russia and China at our Fargo and Williston
Experiment Stations. There is a possibility we will add a third site.
To grow grapes, you need to locate land that has a gentle slope and
is well drained. The slope should have a southern exposure to maximize
good heat units. There should be nothing blocking the cold air drainage
(buildings, dense shelterbelt, etc.) at the base of the slope. If at
all possible, select a site near a large body of water for temperature
modulation in spring and fall. Try to avoid placing the vineyard anywhere
near where adjacent land is going to be sprayed for broadleaf weed control.
You simply cannot give yourself too much of a buffer between land that
is going to be sprayed (especially from the air) because the grape vine
is very sensitive to phenoxy air-borne products. Ideally you should
have a water source available for drip irrigation to carry the plants
through extended drought periods. Be prepared for visits by the local
mammalian rodent populations, including those with antlers. Electric
fencing can be put in place that will offer some protection (9-wire
fence) against raccoons, rabbits, voles, and deer. This can be done
for about $1,000 an acre by a contractor. Work this year to get the
site as weed-free as possible. Kill off existing grassy or weedy vegetation
with RoundUp. Cultivate and allow vegetation to grow before killing
it again with RoundUp in late summer or early fall. Sprinkle a creeping
red fescue cultivar where you will be driving your equipment and till
the area where the vines are to be planted the following spring. Place
your order for cuttings by early February and store damp (moistened
sphagnum moss) between 33 to 40 degrees until planting can take place
in a weed-free location. Incorporate a pre-emergent herbicide like Treflan
or Surflan to keep anything from sprouting while the vines get established
the first year. Growing grapes for commercial purposes is a lot of hard,
dirty work. You might get lucky and make money if the weather, market
and your cultural practices all line up in a favorable manner. I will
be speaking in Williston at the Farm Show in March (17-18). A possible
source for vines is Great River Vineyard, 35680 Highway 61 Boulevard,
Lake City, Minn. 55041. Their toll-free phone number is (877) 345-3531.
They are probably out of some of the varieties I have mentioned. Like
any other new venture, start out small and slowly, so you can afford
to learn from your mistakes. Good luck!
Q: I would like to
know if Manchurian elms have an estimated life span and if they are subject
to Dutch elm disease?
A: What you are
calling the Manchurian elm is also known as the Siberian elm (Ulmus
pumila). So far this species has proven to be resistant to Dutch elm
disease. It has enough other problems such as elm leaf beetle and other
maladies. I guess the Dutch elm pathogen is exhibiting mercy on this
poor cousin to the American elm.
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.
###
Source: Ron
Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu
|
