Dear Master Gardener: There are little pine trees with red bows on them out in stores for the holidays. Do these pine trees do well as a houseplant?
You are probably referring to the Norfolk Island pine (Araucaria heterophylla), which is frequently sold in stores during the holidays as a living Christmas tree. Unlike the conifers you find in local garden stores, which are meant for outdoor planting only, these conifers, native to the Norfolk Islands and Australia, are tropical plants meant for indoor growing in our northern climate.
Poinsettias make an attractive Christmas gift.
When purchasing a Norfolk Island pine, a single-stemmed specimen is best, but typically you will find multiple seedlings in a pot because they look fuller and sell easier. If you purchase a pot with multiple seedlings, you may want to plant the seedlings individually to encourage a single-stemmed tree with symmetrical, tiered branching coming off the main stem, which is characteristic of these plants. In addition, without thinning or repotting, the seedlings will be overcrowded and you will end up with seedlings of various sizes, vigor and poor form.
December gardening tips
Check stored bulbs (cannas, gladiolas, etc.) for rot and discard soft and rotten ones.
There is no need to fertilize new holiday plants for 4-6 weeks. They have been fertilized by growers to last that long.
Buy a fresh Minnesota-grown Christmas tree. They are a renewable crop, grown on land that is marginal for most other agriculture, and are apt to be fresher than imported trees.
Gardening books make great Christmas gifts.
If poinsettias are kept too wet, the lower leaves yellow and fall. If they get too dry, the colorful "petals" wilt and curl.
Prune deciduous trees when they are dormant. Late winter is best.
Norfolk Island pines should not be exposed to freezing temperatures, so make sure to take that into account when purchasing your plant. They require cool temperatures with high humidity and evenly moist soil. Because many Minnesota homes do not have enough humidity for a Norfolk Island pine to thrive, you can increase the humidity around the plant by frequently misting it with cool water.
It is best for all houseplants to use water that is at room temperature. If you have city water, let the water you use for plants sit for 24 hours to dissipate any chemicals (chlorine). Norfolk Island pines need bright light but should not be exposed to full sun. Turn the tree frequently to maintain its beautiful symmetrical shape.
If you decide to decorate your Norfolk Island pine for the holidays, keep in mind that the branches are not very strong, so you may want to use light-weight ornaments or small bows, to avoid damaging your tree.
Dear Master Gardener: What can I use to keep my sidewalk from icing up that won't injure nearby plants or grass?
Commercial de-icers, technically called "salts," work by lowering the freezing point of water below 32 degrees. Salts, however, can damage plants, causing bud death and twig dieback, browning of leaves and lack of plant vigor. Further damage can include shortening the life span of concrete surfaces, corrosion of metal railings and pollution of streams and lakes. Sodium chloride is the most commonly used de-icer. Also used are calcium chloride and calcium magnesium acetate. Calcium chloride is effective up to minus 20 degrees, the others to 15 degrees. All salts should be used only after mechanical snow removal (shoveling or blowing).
The use of abrasives such as damp sand or kitty litter, after mechanical snow removal, creates traction that can keep sidewalks safe without the problems that de-icers present and are the preferred alternatives.
Dear Master Gardener: I'd like to give holiday plants as gifts. What would you recommend?br>
The most commonly sold holiday plants are poinsettias, Christmas cactus, amaryllis, cyclamen and paperwhites. Poinsettias, Christmas cactus and cyclamen are usually sold in bloom. They need bright light and watering when the soil surface is dry. They bloom for extended periods of time and provide winter color. Amaryllis and paperwhites are usually sold as bulbs and bloom 3-6 weeks after being planted and watered. Both may need staking. In recent years florists have begun selling other houseplants, such as ivy, in holiday containers or with holiday ribbons and decor. Most holiday plants come with planting and care instructions.
Dear Master Gardener: I have noticed little bugs flying around my house that I think are fruit flies. They seem to be more prevalent around my plants. How do I get rid of them and will they harm my plants?
The insect you are most likely describing are fungus gnats. If you shake your plant or stir up the soil, you may see a flurry of insect activity. Fungus gnats are usually associated with over-watered houseplants or houseplants that are growing in potting soil that is high in organic matter. They are pesky but do not usually harm plants.
Reducing the moisture in your soil should be your first step in combating the fungus gnat problem. Over-watering is one of the biggest mistakes people make with their houseplants. Allow the surface of the soil to dry out between watering but do not let your plant wilt.
According to the University of Minnesota entomology department, the only effective product for treating fungus gnat larvae in the soil is a bacterial insecticide, Bacillus thuringiensis var. israelensis (e.g. Knock-Out Gnats). Also known as B.t. H-14, this insecticide is specific to fly larvae. However, this product does not kill adult fungus gnats. To reduce the number of adult fungus gnats, you can place yellow sticky cards in the pots. Look for the insecticide and sticky traps in garden centers or order by mail.
CROW WING COUNTY MASTER GARDENERS are trained and certified volunteers for the University of Minnesota Extension Service. All information given in this column is based on research and information provided by the University. To ask a question, call the Master Gardener Help Line at (218) 824-1000, extension 4040, and leave a message. A Master Gardener will return your call.
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