|
November
18, 2004
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: When I was in Fargo
during early July, I saw many beautiful, pink rosebushes covered with
blossoms. Can you give me some insight as to the name of this type of
rosebush and type of care it requires? (New Rockford, N.D.)
A: Sorry, I can’t.
Perhaps a reader will know what they are. If someone does, I’ll
put it on my Web site and share the information in my column.
Q: I have several
rows of strawberry plants, but I don’t get very many strawberries.
Some of these plants are 2-years-old and some are 3-years-old. Should
I cut suckers off? What kind of fertilizer would help and how often should
I use it? Why do I get so few strawberries? Also, when is the best time
to prune and thin out raspberries? Can I cut the tops off so the plants
are shorter? It’s easier to put a net over shorter plants. (Munich,
N.D.)
A: Strawberries
send out runners, which you want to encourage. They should be mowed
down this fall after a couple of good frosts. I would then throw some
super-phosphate over the patch. Next spring, spread some 10-10-10 over
the area before new growth begins. If their production doesn’t
improve, dig them out and replace with a new planting. Raspberries bear
on biennial canes. The canes die once they have finished bearing. The
young canes coming up from the crown that are not bearing this year
will bear next year. Remove the old bearing canes when they are no longer
producing fruit. With the new growth, cut out the weak, spindly canes
and space the remaining canes about 10- to12-inches apart. Early next
spring, before new growth begins, cut the canes back to the height you
want them to be and dispose of the cuttings. New growth will emerge
and the plants will be a more manageable size.
Q: What is wild rhubarb?
I have plants that look like rhubarb, but grow a center stalk with seed
(burrs) that stick to your clothes. I consider them nuisance weeds. I
have observed other plants that look just like rhubarb, but with no center
stalk. What is the difference? Which plants, if any, are safe to harvest
and eat? (e-mail reference)
A: What you are
describing is Burdock, Articum minus, which is in the sunflower family
(Asteraceae). Rhubarb is in the buckwheat family (Polygonaceae) and
is closely related to curly dock, Rhumex crispus. Common names are deceptive
and one shouldn’t make judgments based on those, especially if
you are considering eating it. It isn’t worth taking the chance
unless you are absolutely sure of what you are looking at and you know
of someone who has eaten the plants and lived to talk about it.
Q: We’ve received
a lot of calls about cottonwood trees dripping a sappy liquid. Is this
something that can be treated with insecticidal soap? If so, where do
you purchase the soap and how is it applied, especially on very tall cottonwood
trees? (e-mail reference)
A: The problem is
usually caused by aphids. Spraying with insecticidal soap will take
care of this pest because they are soft-bodied and vulnerable to low-toxicity
insecticide. Any garden supply store, nursery or garden center should
have it. On large trees, there is no other way to apply insecticidal
soap except using a high pressure sprayer that is available only to
professionals in the business. Sometimes predatory insects arrive and
begin bringing the aphid population under control, but this is a hit
or miss situation.
Q: We have chokecherry
trees in our shelter belt. A few years ago we had so many chokecherries,
but we haven’t had any the past few years. The trees have buds and
unripe berries at the beginning of the season, but they are gone by the
end of June or early July. Are birds eating the unripe cherries or is
it a different problem? Our neighbor has a row of chokecherries in his
shelter belt that produce a lot of fruit. (e-mail reference)
A: The trees simply
over-bore last year, so now the trees have to recover and accumulate
energy to bear chokecherries next year. If the trees are healthy, then
this should be the cycle. Perhaps you and your neighbor could get together
on the off years and share your crops.
Q: I am concerned
about some spruce trees in the front of our house. I am aware that spruce
trees grow cones in order to reproduce in case of a fire. If a spruce
tree grows a ton of cones, does this mean it is about to die? I’m
concerned about a tree falling on my house. (e-mail reference)
A: Evergreens will
produce cones at maturity and vary the production rate based on the
environment. Most landscape trees are grown under stressful conditions
so, depending on the year, this could result in greater than average
cone production. Cone production is often overwhelming if the tree is
losing its vigor. If the tree is otherwise healthy and has produced
decent new growth for the season, then the tree is in no danger of collapsing.
Have the tree checked by an International Society of Arboriculture arborist
to be on the safe side.
Q: I’m looking
for the correct name and history of a plant commonly known as Indian tinker
toy. I have it in my pond. (e-mail reference)
A: I’ve known
it as common horsetail, Equisetum arvense. It’s commonly found
in wetlands and spreads by way of rhizomes (underground stems). It is
a common food for wild geese and winter forage for deer. Native Americans
and early settlers used the plants to clean cooking utensils.
Q: I have a crabapple
tree that is bearing a lot of fruit, but I can’t find anyone who
can tell me when the fruit is ripe and ready to make jelly. (e-mail reference)
A: Without knowing
where you live, the conventional wisdom is to wait until after the first
frost. Generally, late August to early September is a good time.
Q: I have orange spots
on the leaves of my valiant grape vine. The grapes are turning a red-blue
color and withering away. (e-mail reference)
A: Controlling diseases
on grapes is not difficult, provided you follow strict disease control
practices such as pruning, cultivating and spraying. If you are not
prepared to carry out all three practices, you will not be a successful
grape grower. Of all the diseases that can affect grape growing, your
description appears to fit that of the fungus, downy mildew. The fungus
attacks all the green parts of the vine. Initially, lesions are yellowish
and oily and then become angular with yellow to reddish-brown spots.
Infected shoots thicken and curl, then turn brown and die. Young berries
become gray when infected. The fungus overwinters primarily in infected
leaves on the ground. It may also survive as mycelium in buds during
mild winters. Pre-bloom sprays are necessary for control. Unfortunately,
there is nothing that can be done now. Spray with a Bordeaux mixture
next spring as foliage unfolds and again 10 days later. Repeat in 30
days. The best action is sanitation, so excellent fall clean-up is essential.
Q: I need to transplant
some lilies (oriental and tiger). When is the best time of the year? Any
tips would be greatly appreciated. (Arlington, S.D.)
A: The best time
is early spring or fall after a hard frost.
Q: We are considering
getting a dog, but have a large crabapple tree in our back yard. We do
not know the type, but we’re concerned the dog may get sick if it
eats the apples. (e-mail reference)
A: I have had dogs,
so I know they will eat just about anything that they shouldn’t,
but I’ve never had one that ate crabapples or any fruit for that
matter. If the dog does get sick, it will be minor and temporary and,
unless the dog has Swiss cheese for brains, it wouldn’t make the
same mistake again. Get your dog and enjoy the company it will provide.
You will benefit in the long run.
Q: I decided to see
if I could start a new gloxinia after it finished blooming. I planted
three leaves with roots. Out of the three, one developed into a plant.
The plant had over twenty blooms, but most of the blooms never grew large
enough to open. Of the few that did, the stems turned brown and fell off.
From what I have read, I must have been overwatering. How often should
they be watered, and what kind of light do they like? Any suggestions
on how I can get the flowers to open? (e-mail reference)
A: Congratulations!
You are among the brave and few who have gone this far.
Gloxinias are fussy
about their water and room temperature. They don’t like many chemicals
and never on the leaves. If the air temperature drops to 65 degrees
or lower, reduce the watering frequency and allow the top inch to dry
out before re-watering. Gloxinias need bright, but filtered light, which
is probably why your plant blasted the buds instead of opening.
Try your luck again and if you get really good at it, go into business!
Q: A client has a
hibiscus (small tree type) and is wondering what the best way is to keep
it over winter. I assume that it needs to be taken inside for winter,
but do you let it go dormant for the winter or try to keep it leafed out
and growing inside the house? It’s growing in a large pot. (e-mail
reference)
A: There are probably
at least a half dozen ways to get hibiscus to make it to the next outdoor
season. What I have found that worked for me, is to allow it to get
nipped back with frost and then bring it into the garage where it can
stay cool or cold for six to eight weeks. Then prune it back hard and
bring it into a setting that gets ample light and warmth. Start watering
to keep the media moist. Leaflets should break out shortly and the plant
will reward the owner with a bloom or two during the long winter months
if there is enough light. Give the plant a shot of fertilizer as the
new growth begins.
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
|
