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February
16, 2006
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: We planted arborvitae
across a section of the yard close to a wooden fence. The plants did great
for a few years, but last summer they began to thin. We fertilize the
plants with Hollytone twice a year. At this point, they are extremely
thin and no longer offer the privacy we want. Can you offer any advice
to revive the plants? (e-mail reference)
A: Thinning of evergreen
arborvitae foliage, without any visible disease or insect problems,
is usually associated with environmental conditions, such as too much
shade. If that is the case, you need to move the plants to improve sunlight
penetration or pull them out because they will not improve under the
present conditions. If shade is not a problem, then examine the planting
depth. If they are planted too deeply or covered with too much mulch,
then pull some of the soil or mulch back to the crown, which is where
the stem meets the roots. Fertilizing twice a year is not necessary.
Save yourself money and time.
Q: We have two snow
flowering crab apple trees and an autumn maple tree. I would like some
information on how to prune these trees. I tried to find your Web site,
but was unable to find it. Can I get the address so I don't need to bother
you? (Webster, S.D.)
A: Go to Google
and type in Hortiscope or you can type in the header www.ext.nodak.edu/extnews/hortiscope/contents.htm.
That will take you to the opening page, where you can navigate to your
heart's content. If you miss the publications listing, one of which
shows proper pruning techniques, then go to www.ext.nodak.edu/extpubs/trees.htm.
At that address, you will see the listings and can select H1036, "Pruning
Trees and Shrubs."
Q: Is softened water
bad for my houseplants? (e-mail reference)
A: Softened water
uses sodium ion to replace calcium ion in the water supply. With time,
it will kill just about any houseplant. It is better to use distilled
or unsoftened water.
Q: I have five large
dogs and a well-established shelterbelt on the west side of my two-acre
lot. Would it be a bad idea to use the dogs’ solid waste as fertilizer
for my shelterbelt? What should I know about spreading the piles? Should
I mix anything with it, such as lime or tree mulch? I do nothing to the
trees in this shelterbelt. I let the weeds grow and have not cleaned out
fallen branches. Should I be doing these things? (Mandan, N.D.)
A: Spreading the
dog manure on the shelterbelt planting would be a good way of disposing
of the waste and certainly wouldn't hurt anything. I would suggest that
you compost it with leaves or grass clippings to give it some fiber
and dilute it somewhat.
I have spread chicken and cattle manure in my day and became used to
the smell. If I could get used to the smell of accumulated dog droppings
is another question. Of course, the more care you give the shelterbelt
plantings, the longer they will last and reward you. Weeding and pruning
would be just the basics to engage in on a regular basis.
Q: I have a weeping
willow that I planted last July. It was growing very well and getting
a lot of water. Then I noticed some irregular borders around some of the
leaves, but only found one grasshopper and no other insects. All of the
leaves started to turn yellow and fall off. There was a sawdust consistency
to some shavings, which were medium brown and occurring at the joints
of the tree branches. Three branches died and had to be removed. Do you
have any recommendations? (e-mail reference)
A: It’s bad
news. The problem sounds like the tree has been invaded by borers. At
this stage of the tree's life, fighting it is not worth the effort.
Yank the tree out and begin again. Next time, carefully inspect the
tree for borer or other destructive insect activity before planting.
Q: Which version of
campsis radicans does best in Grand Forks? Also, what are your five best
perennials for attracting hummingbirds and are hardy in Grand Forks? (e-mail
reference)
A: I would encourage
you to contact Steve Sagaser, Grand Forks County horticulturist, for
more details beyond what I will give you. He can be reached at stevan.sagaser@ndsu.edu.
To my knowledge, the trumpet creeper is not dependably hardy in the
Grand Forks area, but this is where Steve would know better than I would.
As for the perennials, I can give you some tough ones that I've planted
here in the banana belt of Fargo that should do equally well in Grand
Forks. They include anise hyssop (Agastache foeniculum), bee balm (Monarda
didyma), delphiniums (Delphinium spp.), cardinal flower (Lobelia cardinalis),
geranium (several cultivars) and daylilies (Hemerocallis spp.). Prairie
gayfeather (Liatris spp.) also should survive in your garden because
it is native to our region. Perhaps Steve can add or correct this list
for you.
Q: I inherited a Christmas
cactus after my mother passed away in August. I tried before to care for
a piece that belonged to my great-grandfather, but it died. My mother's
cactus is part of the one owned by her grandfather. It was doing great
while she cared for it. Since I've had it, most of the plant looks fine.
However, a section kept wilting. Today I was able to peel a part of the
bark from the stem, but that part of the plant pulled out of the soil.
The part that came out is substantial, approximately 15 inches of the
plant! I don't know what to do. I put the section into water to see if
I can get roots to form, but won't that rot the plant? Should I cut sections
off and try to root them? I really don't want to lose this plant and am
desperate for some help. This Christmas cactus was my mother's pride and
joy, partly because it looked so great and because it was a piece of her
grandfather. I told my mother I wouldn't be able to properly care for
it and I feel as if I am letting her down. If you have any advice, please
pass it along. (e-mail reference)
A: Take some sections
and root them in a sand/peat media. Keep it moderately moist and in
bright, indirect light. The sections should root for you in about six
to eight weeks.
Q: I have an aloe
plant that I had to repot during the summer. It appears that fungus gnats
were in the soil and infested all the plants in my office. I tried several
ways of getting rid of the bugs. I ended up throwing the soil out and
putting the aloe plant in water, which got rid of the pests. However,
I need to put the plant back in soil, but I am gun-shy about the potting
soil. The potting soil remained in my truck for about a week in below-zero
temperatures. If there were any fungus gnat eggs in the soil, would they
have survived the freezing temperatures? (e-mail reference)
A: Where are you
getting this potting soil? Most potting soil on the retail market is
pasteurized or sterilized. Freezing temperatures will take care of any
adults, but as for the eggs, I wouldn't bet the farm on it. If you must
use the soil from the back of the truck, microwave it first for about
two minutes in an open bag. It will not smell nice, but that should
take care of anything that might hatch out. Go to www.ext.nodak.edu/extpubs/plantsci/landscap/pp744w.htm
for complete information on this procedure, along with other tips for
solving houseplant problems.
Q: I hope that you
may be able to help me save my son's croton houseplant. He received it
from his teacher when he was in kindergarten. He is now in the fourth
grade. It was a very small plant when the plant was given to him. The
plant grew to about 8 inches and appeared very healthy until a few weeks
ago, when it started to lose its bottom leaves. The leaves were dry and
brittle when they fell off. Then the same dryness and brittleness began
to affect the remaining upper leaves. Today, the last leaf on the top
of the plant was so dry and brittle it broke off while I was watering
the poor plant. My son is heartbroken. Can the plant be saved? Might cutting
it back or repotting it help? Thank you. (Roseglen, N.D.)
A: Having the plant
stay vigorous from kindergarten to fourth grade is a good accomplishment,
so you or your son must have been doing something right.
Croton houseplants
amaze me. They are noted for their fussy environmental requirements,
but there is one right at the entryway of the Northland Educators Federal
Credit Union that thrives on all kinds of abuse, such as cold drafts
from the opening of the main door, undependable light intensity and
duration, and when-they-think-about-it watering. Who knows if it has
ever been fertilized, repotted or misted! All I can tell you to do is
to check the bark on the main stem with your thumbnail and see if the
tissue beneath is still green. If it is, there is a chance for recovery.
If not, then you might as well dump it and start over. The only thing
I can think of to have it succumb after so many years of success is
that you or someone has changed the routine or location the plant had
adapted to. As I tell them at the credit union, don't change anything
because it could kill the plant if they suddenly started taking care
of it the right way!
Q: We have enjoyed
feeding suet to our downy woodpeckers during the past few years and were
thrilled this fall to see that a huge, hairy woodpecker had discovered
our feeding station. Thrilled until I started noticing some of the huge
holes the woodpecker made in our trees. The bird has drilled a hole halfway
through one of our young ash trees. Will woodpeckers kill a tree and should
we discourage the birds instead of encouraging them to entertain us from
our kitchen window? I enjoy reading your column. Keep up the good work.
(Linton, N.D.)
A: Thanks for the
nice comment about the column! We have had occasional visits from members
of the woodpecker family in our backyard, but then they take off. I
never have heard of a woodpecker's activity doing enough damage to kill
a tree, but a big hole in a tree isn't going to do the tree much good.
Since they are creatures of habit, I suggest getting some Tanglefoot
and carefully rubbing it around the area where the woodpecker is frequenting.
I say carefully because it is messy stuff, but it usually does the job.
Perhaps the woodpecker will be content eating your suet, rather than
trying to attract a female!
Q: We have had a spider
plant for several years. We put it in a new pot and location. It was doing
great. It started to get very large and looked beautiful. After six months,
the plant has started turning brown and yellow and leaves are falling
off. I thought I might have been overwatering, but then I realized that
the new pot didn't have holes for the water to drain. We have since drilled
holes in the pot, but it doesn't seem to be helping. I wonder if the roots
are rotting. Is there anyway to save it? (e-mail reference)
A: People really
have to work hard to kill these tough plants! Repot it with fresh soil,
but make sure it is in a free-draining container. Do not put gravel
on the bottom for drainage! Place a piece of crockery over the hole
to keep the soil from washing out too fast. Try to put the plant back
where you had it originally or create a similar environment.
Q: We recently moved
and since then our staggered Madagascar tree has lost its leaves. It has
three stems. The one without leaves has a stem that seems to be drying
out. I have had this plant for 17 months and would hate to lose it. I
have tried placing it in different rooms, giving it Miracle-Gro and repotting
it. The leaves on the other branches are a light green instead of a darker
green. This plant has changed dramatically since we have moved. Is there
a way to save this plant? (e-mail reference)
A: Here are the
requirements for this species. First, it is a false palm, meaning that
it characteristically has a whorl of foliage on top of a bare stem.
Yellowing of the older foliage is natural as the tree ages. The plant
also needs to have the soil kept moist, but the amount of water should
be reduced by probably 50 percent during the winter months. Speaking
of winter, while the dragon tree can tolerate cool temperatures, it
cannot go below 55 degrees or else problems will occur. Finally, it
needs good indirect light, but not direct sunlight. This would mean
putting it in an east-facing window, just outside the impact of direct
sunlight. If you follow these basic recommendations, I think your tree
will recover.
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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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