Gardening
for Your Watershed – November 2003
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This month’s
topics:
* Houseplants
* Pest of the Month: Winter Moth
* General Gardening Tips
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Houseplants
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The outdoor gardening season may be mostly over, but your indoor plants still need attention. Do they have droopy leaves? Yellow foliage? Unusually long stems? Before you reach for the watering pot or the fertilizer, check this list and see if you’re being naughty or nice to your houseplants.
- Problem: Your plant is leggy (stems are abnormally long). Solution: Give it
more light. Try moving it to a southern exposure, or putting
it closer to the window.
- Problem: Leaves look wilted. Solution: Your plant may be getting blasts of either
hot or cold air, the overall room temperature may be
too cold, or it may not be getting enough water.
- Problem:
Leaves look wilted and there is a white, crusty layer on top of the
soil. Solution: Salts have accumulated in your soil, which
causes dehydration in your plants. If you can put the plant in your sink,
rinse out the salts by running water through the pot (about three times
the volume of your pot). If the pot is too big or heavy to put in the
sink or to take outside, water the plant thoroughly, wait 30 minutes,
and then water it thoroughly again.
- Problem: Leaves are yellow. Solution: This is a symptom for many problems. Are
you overwatering your plant, which rots roots? Not
giving it enough sun? If all other solutions fail, you might need to
lightly fertilize your plant.
- Problem: Leaves look like they’ve been bleached. Solution: Reduce the amount or intensity of sun that your plant is receiving.
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Pest of the Month: Winter Moth
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If you see a moth flying around outside this time of year, chances
are it’s a winter moth (Operophtera brumata). This is
the time of year when adults emerge from the soil and start looking
for mates. The wingless
females will climb up tree trunks and lay their eggs. As larvae start
to hatch out in March, they’ll ravenously devour the leaves and
buds of blueberry plants, flowering trees such as apples and cherries,
and other trees such as oaks and maples.
While the winter moth population is mostly likely to boom after wet summers and mild, moist autumns--which doesn’t describe the weather this year--it’s still a good idea to check your trees. Adult males are grayish brown with 1” wingspans, females have no wings, and larvae are green inchworms with white “racing” stripes on their sides.
At this time of year, keep a lookout for clouds of moths around tree trunks in the evening. They usually signal the presence of a female on the trunk, which will be easy to capture.
In the spring, look for the juveniles. During the day, you’ll find them nibbling away inside buds and leaf clusters. At night, they’ll be on the outsides of leaves.
Decision-making:
- As with most pests that cause leaf loss, established trees can bounce back from up to 25% leaf loss.
- Consider that winter moth is a cyclic criminal. It's here one year, gone the next.
- Trap female winter moths on their way to mate and lay eggs. Put a 3-4" wide sticky barrier on tree gauze around the trunks of infested trees. Both the sticky stuff and gauze can be bought at garden stores for less than $10.
- You can suffocate winter moth eggs by applying dormant oil to your tree from November to January. Follow the label directions carefully to avoid scalding leaves.
- Bacillus thuringiensis (B.t) is deadly to caterpillars, yet it's less toxic to other wildlife than most insecticides. It works best on young caterpillars, so spray in early spring on a cloudy but warm day. (Sunlight breaks down B.t.)
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General gardening tips from WSU and OSU Master Gardeners
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* Are your rhodies and azaleas looking sickly because of the cold snap? Don’t worry, they’ll bounce back. They haven’t yet had a chance to go fully dormant. Some of your other woody plants may be showing cracks because they got caught with too much moisture in their bark--try protecting them by mounding chips or sawdust around them. Read more at:
Garden
Hints: Early winter cold may be tough on rhodies and azaleas
* Going away for the holidays? Water your houseplants thoroughly, pour
off any excess water, and then put them in a clear plastic bag. Then
set them in indirect sunlight.
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This newsletter
is produced by Whatcom County Extension. To subscribe or unsubscribe,
or to make comments and suggestions, please contact Scarlet
Tang or
360/676-6736.
