|
7-3-02
Question and Answer
Q. An insect is killing my schefflera. It gets white, fuzzy-looking
places on it that feel soft, and you cannot see the insect that is working
on it. Finally, it will kill the leaf if not removed. I wash the leaves
from time to time with soap and water, and last time a little bleach.
It works for a while. I even tried a fungus product and worked it in the
soil after giving the plant a bath. Help! I like the plant but need to
know what to use on it. -- Janice Corwin
A. Mealybugs congregate where the leaves attach to the stem or
around major veins on the undersides of leaves. They appear to be dusted
with a fine, white flour and, sometimes, have long, waxy filaments extending
from their bodies. They are slow-moving, wingless insects that are protected
by their waxy covering. They remove plant juices with their sucking mouthparts,
resulting in yellow, distorted leaves.
Spraying plants with forceful streams of water often washes off and kills
smaller insects. Individual insects can be removed with a toothpick or
tweezers. Or you can wet or remove each insect with a cotton swab dipped
in isopropyl alcohol. You must recheck the plant every two weeks or so
to be sure you have removed all of the insects. Alternatively, you could
treat the plant with an insecticide. Resmethrin and insecticidal soaps
are listed for mealybugs. You can make your own insecticidal soap by mixing
4 teaspoons of dishwashing liquid per quart of water. Don't spray on any
flowering plants or particularly sensitive plants like African violets
or ferns.
The fungicide you
applied will only protect a plant from fungal pathogens and will not have
any affect on insects or other pests. Be sure to identify the particular
problem before using pesticides. It's better for your health, the environment,
the plant in question and your pocketbook!
Q. I have tried and tried to identify this plant by searching in
many wildflower, weed and herb books but can't identify it. Since I found
it near my dad's woods beyond the cornfield, I do not know what color
the dense spikes were, as we only go to the area after harvest, which
is after frost.
I am sending an end
seed piece, a piece of the stem and a sketch of the plant. Here are the
clues for identification: it grows 6 feet tall, has a square stem and
has 4-6-inch erect flower spikes.
The closest I've
come to identifying it is Agastache nepetoides, but it doesn't get that
tall, so that can't be it. -- Janice Teel, Mentone, Ind.
A. Good work! I often receive plant descriptions that are missing
important bits of information, making it impossible to identify the plant.
And you actually solved your own mystery, since the plant in question
is, indeed, Agastache nepetoides or yellow giant hyssop. This is a perennial
that can reach a height of 7 feet. (I'm guessing that you had a reference
that said otherwise, but it really can!) The flowers are yellow-green,
sometimes almost white, and appear from late summer into early fall. While
this is most often found growing wild, it can be a nice addition to the
back of the perennial garden, since it has an extended bloom time and
some architectural interest.
Agastache is a member
of the mint family, which is easily recognized by the square stem. Nepetoides
means it looks like catnip (Nepeta). It is attractive to bees and butterflies
and prefers thin woods, thickets and openings.
Q. About 10 years ago, I purchased four hardy kiwi plants that
were supposed to be three female and one male. They have grown very well
-- but no fruit!
I'm having a similar
problem with persimmons. A friend gave me two trees about 8 years ago,
and they have grown very well -- but no fruit! I check every year for
blossoms, but I don't think I see any. I don't understand the "birds
and bees" of these plants. Can you help me? -- Ozzie Luetkemeier,
West Lafayette, Ind.
A. The kiwi vine that produces fruit like that in the grocery is
Actinidia deliciosa, and it is dioecious, meaning male and female plants
are required for fruit production. Even the supposedly self-fruitful cultivars
do better with a pollinator. Actinidia deliciosa isn't really hardy in
Indiana. If the plants do survive, the flower buds would almost always
be killed during winter and early spring freezes.
There is a hardier, self-fruitful kiwi vine, Actinidia arguta, but the
fruits are much smaller, like large grapes. If this is the cultivar in
your garden, you should have better luck. Sometimes, they don't produce
for the first 5-9 years, but you've passed that hurdle. I suspect that
yours are all of the same gender (are all four still surviving?), or they
are succumbing to late spring frosts. While the roots are hardy to –30
F, the tender shoots are extremely susceptible to spring frosts. You may
want to cover them with a sheet or spun polyester blanket (available through
garden catalogs or in garden centers) during frosts. More information
on hardy kiwis is available at http://ssfruit.cas.psu.edu/HardyKiwi.htm.
The native persimmon
is botanically known as Diospyros virginiana. The species is native throughout
the lower Midwest and the southeastern states. It is known to be hardy
to temperatures of -20-25 F without apparent winter injury. The native
persimmon is a small tree, but may often reach a height of 40-50 feet
and occasionally even larger under ideal conditions.
The greenish-yellow
flowers are borne on very short stalks. The staminate (male) flowers are
usually borne in threes, are about one-fourth to one-third inch long,
and usually contain 16 stamens. The pistillate (female) flowers are borne
singly, ranging one-half to three-fourths inch in length with four two-lobed
styles.
The persimmon is
dioecious, that is, each tree produces only either male or female flowers.
This means that both male and female trees are usually necessary to produce
a crop of fruit. The native persimmon is regularly dioecious, with male
trees producing only staminate flowers and female trees producing only
pistillate flowers. Only in rare instances are trees self-pollinating.
When planting seedling
trees, be sure that you have female trees, if fruit is desirable. This
can only be proven by fruiting the trees. For positive fruiting, both
male and female trees should be planted. The exception is that in the
natural range of the persimmon, adequate wild trees will be available
for pollination. As an added thought, if the trees are intended for ornamental
purposes only, and fruit is not desired, then a male tree might be selected
to eliminate the problem and mess of dropping fruit.
It is probably best
to obtain budded or grafted trees from a reliable nursery to be sure of
getting the type of trees you want and trees with desirable fruit characteristics.
Care of the persimmon
is minimal. Fertilization is not usually necessary, other than the fertilization
that would normally be given to a lawn. Pruning is not usually needed,
except to limit tree size, and to correct faults such as dead or broken
limbs.
Again, chances are
good that you have two trees of the same gender, or they have not quite
reached maturity. It can take 10 or more years for persimmons to begin
fruiting, although some will begin much earlier.
The oriental persimmon,
Diospyros kaki, is not native to Indiana and is not adapted to Indiana
conditions. Hoosier winters are too cold to permit cultivation of this
species, except in rare and very protected situations. It is not hardy
below about 10 F. This is the species of commerce and is grown commercially
in southern areas of California. The fruit ranges to 3 inches across and
is seedless in most varieties. Nursery catalogs frequently advertise this
species, but Indiana gardeners are cautioned against purchasing plants
of D. kaki.
|
