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March
17, 2005
Hortiscope
Ronald C.
Smith, Horticulturist
NDSU Extension Service
Q: I have a Spanish
dagger tree in my home. I was told it was an indoor plant, but I’ve
discovered it’s not. Many of the leaves have started turning yellow
and dying. I thought the amount of light the plant receives might be the
problem, so I recently installed a 75-watt grow light above the plant.
I give it a half-gallon of water once a week. I don’t know about
the watering (amount for pot size, frequency), the light or if it can
live inside. (e-mail reference)
A: I think you mean
the plant is a Spanish bayonet, which actually is the Yucca aloifolia.
It is an attractive indoor plant. Keep in mind that environmentally
and botanically speaking, there is no such thing as an “indoor
plant,” only plants that we want to grow indoors. You did the
right thing in providing supplemental light. Be conservative with watering
during the winter months and liberal during the summer months. Like
many houseplants, the Spanish bayonet will benefit from being summered
outdoors. That is, if it doesn’t take a football center and fullback
to move it for you! I think the reason you are losing some foliage,
based on your description, is because of overwatering or the container
is not freely draining. You can propagate this plant by cane cuttings
or air layering. For propagation details, go to this Web site, www.ext.nodak.edu/extpubs/plantsci/landscap/h1257w.htm.
Q: The leaves on
my bamboo plant are becoming a lighter green. Can you tell me how to care
for this plant? I also have a pothos gold that I keep in water. Can you
give me any tips on keeping these plants healthy and growing? (e-mail
reference)
A: I’m guessing
that you are overwatering the bamboo plant during the winter months
and possibly keeping it too warm. Bamboo does well in an unheated room
during the winter, so try to locate it in the coolest place in your
home and cut the watering in half. With the pothos gold, pot it with
quality potting soil. Pothos gold is one of the most idiot-proof plants
to grow indoors. Give it anywhere from 150 to 200 foot-candles of light
or more, but not direct sunlight. Water it occasionally. Fertilize it
during active growth. Pothos gold will lose its variegation if the light
intensity is too low. We have had a couple growing in our office for
more than 10 years. We cut them back and root the cuttings. The plants
continue to grow even with our sometimes lack of care. In fact, a favorite
Mexican restaurant has had one growing across the ceiling for years.
Q: I have a surprising,
but impressive situation with my dracaena reflexa (song of Jamaica, I
believe). I stuck a cutting in water a couple of months ago (October)
and never got around to planting it. It has been sitting on a poorly lit
and insulated window sill all winter. I felt bad about it, but didn’t
do anything. It grew roots in the water, put out one or two leaves and
suddenly decided to produce fruit. The tip is generating cream-colored
seeds, micro-flowers or something else. Should I plant it now? Can the
seeds be planted? Can I save them? Is this common? (e-mail reference)
A: When plants are
under stress, they often go into a “shocked” reproductive
mode. The plant is “happy” with the care you are giving
it and is remaining in a physiologically juvenile state (non-reproductive)
because the conditions for vegetative growth are maintained beyond the
optimal. That’s one possible explanation. It could be the plant
has not accumulated enough carbs to go into a reproductive stage. This
might sound like a contradiction, but the plant may be using up its
reserves to perpetuate it by going into a reproductive state. Perhaps,
based on the genetic factors for plant growth and reproduction, not
all the “ingredients” for reproduction are in place. This
doesn’t hold true 100 percent of the time. Almost nothing does
in biology. There are predictions, expectations and exceptions. I often
recommend “traumatic stimulation” on nonbearing apple trees,
which is the driving of a straightedge spade into the ground around
the canopy edge of the tree in several places. This shock treatment,
a sudden reduction in root volume, starts the reproductive cycle.
Q: Someone called
in on your radio show and asked about the importance of rotating crops
in your garden. Your answer was clear, but it didn’t address my
problem. My garden is just a small plot on the south side of my house.
I usually plant three tomato plants, some basil and eggplant. Since the
tomatoes and eggplants are from the same family, I can’t rotate
the two. (I was going to skip the eggplants this year because they haven’t
been doing well). I’m interested in the tomato plants because they
taste so good and do very well in this warm, sunny spot. Is there something
else I can do instead of rotating? Can I add something to the soil? I
guess I’ve been lucky because I’ve never had disease problems,
but it sounds like I’m on borrowed time. (e-mail reference)
A: Thanks for being
a loyal listener to our program. Your problem is common with small-scale
gardeners. You can practice excellent sanitation with good fall cleanup
and spring preparation, and whenever possible, select tomato cultivars
that are disease resistant. If they have a string of letters behind
their name, such as V,F,N,T and A, it means that the variety is resistant
or tolerant to most major tomato problems. Generally, new hybrids have
resistance bred into them. It is mostly the heirloom or older varieties
that are disease prone and need rotating between families. Thanks for
the good question!
Q: I received a peace
lily from my husband for Valentine’s Day, but I don’t have
a clue how to care for it. I love the plant and would like to keep it
for many years. The plant has five blooming flowers and is healthy. How
many times do I water it? How often do I repot it? What do I do from season
to season? How do I tell when it’s too big for the pot? (e-mail
reference)
A: Some varieties
can flower over a long period and may have flowers coming and going
at the same time. Others may come into bloom with a flower or two and
slowly wither away. Generally, you will notice that the flowers expire
in a couple of ways. After pushing up their pure white hoods above the
foliage, the flowers can be enjoyed for weeks, even months. When they
have reached the end of their cycle, the flowers begin to die. The white
hoods may begin to discolor and get brown spots, about the same as cut
flowers. The flowers also can begin to turn green slowly. You may experience
both of these conditions on the same plant. It is not unusual to find
the flowers turning green when they have been pollinated and seed has
been set. You can extend the blooming time by keeping water off the
blooms. Flowers consume energy. When the bloom starts fading, it’s
time to remove it. You’ll notice that the flower stalk comes up
next to the leaf petiole. Don’t remove the flower and leave the
flower stalk. Remove the flower stalk as far down as possible without
cutting off the leaf. Be sure to cut the stalk and not rip or twist
it out. Leaving the flowers on for an extended period can cause the
new leaves to come out smaller. This is from the energy used in flower
production. Spathiphyllums are excellent foliage plants, even without
flowers. Enjoy your plant while it is in bloom and then enjoy this tough
indoor plant for its foliage. For more information on general houseplant
care, go to my Web site at www.ext.nodak.edu/extpubs/plantsci/landscap/h1260w.htm.
Enjoy!
Q: I have a maple
tree in my yard that, in many places, is leaking what appears to be water.
Is this a sign it is dying? Any help will be appreciated. (e-mail reference)
A: The leakage is
a carbohydrate-based material. The leakage could be due to (depending
on where you are located) woodpecker/sapsucker or borer damage or simply
slime flux (bacterial wetwood). The difference is the length of time
the tree will ooze liquid. If it stops in a few weeks to months, it
was caused by shallow wounds. If it persists for the whole year, then
it is an infection of the inner sapwood or heartwood. There is no effective
treatment for this problem, but to put your mind at rest, it is common
in maples. You might want to have an International Society of Arborists
certified arborist inspect the tree. If it turns out to be borers, it
could be the end of your maple if it isn’t brought under control.
Q: What do you know
about Plantskydd Deer Repellant? The local Soil Conservation District
is planning to sell the product this year. Does it work? (e-mail reference)
A: It is highly
rated. It is considered an organic way of controlling the grazing animals
and acts as a mild fertilizer on the plants that receive the treatment.
It is blood hemoglobin mixed with vegetable oil. It is said to have
a lasting effect up to six months in winter and three months during
the summer. It is most effective when applied before the deer start
eating the plants. Apparently, when deer begin to graze in a certain
area and on specific plants, it is difficult to dissuade them! The Minnesota
Department of Natural Resources has been using Plantskydd in about two
dozen districts. It originated in Sweden and now is produced in the
United States.
Q: I have seen people
grow beautiful flowering and foliage plants in the same pot. I would like
to know what kinds of flowering plants I can plant with spider plants
to add color. I also have heard of spider plants producing their own flowers.
Is there a type of spider plant that is more likely to produce flowers?
(e-mail reference)
A: Spider plants
are usually stand-alone plants because of the massive foliage, runners
and spiderettes they produce. However, this shouldn’t keep you
from experimenting and informing us of the results. You might want to
begin with something that is as, if not more, aggressive than the spider
plant at overwhelming a container. You may want to try a wave petunia.
Q: Do you know about
a natural herbicide produced by box elder trees? I have noticed bare ground
around some box elder trees that can’t be caused by a lack of sunlight
or something else. I know walnut trees secrete juglone. (e-mail reference)
A: My references
don’t specify the box elder as having an allelopathic effect on
surrounding seedling invasions. The references do state that competition
is very common among species to assure their survival, especially where
plant growth resources are limited, such as in droughty or dry land
areas. Leaves and roots, as you probably know, are the most common source
of these inhibitors.
Q: We heat our home
with wood and have a lot of ashes. What are some good uses for the ashes?
We were putting them on the garden, but I think it has changed the pH
in the soil too much. Can we put the ashes around our blue spruce trees?
(e-mail reference)
A: Wood ashes are
high in pH values and potash, which can be leached through rainwater.
If you live in a high acid soil region, that actually would be beneficial.
If the soil is alkaline, above pH 7, then problems could exist. In that
case, I would incorporate the ashes into composting material so the
alkalinity of the material can be reduced. Some application around a
spruce would not hurt anything if the above situation applied. However,
continuous applications could lead to some problems, such as a tie-up
of the metallic trace elements.
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.
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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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