Archive for » 2009 «
HOUSEPLANTS
•On cold nights, move houseplants back from icy windows to prevent chilling injury.
•Over-wintering geraniums like bright light and cool temperatures. Keep soils on the dry side.
•Be sure newly purchased indoor plants are well protected for the trip home. Exposure to icy temperatures for even a few moments may cause injury.
•Water houseplants with tepid water. Cold tap water may shock plants.
•Holiday Poinsettia basics:
- sun for at least half the day.
- keep away from drafts, registers and radiators.
- night temperaturesin 50’s or low 60’s, days at 70 degrees.
- the soil should dry only slightly between thorough waterings.
- discard the drainage.
- be sure to punch holes in decorative foil wraps to prevent soggy soil conditions.
ORNAMENTALS
•Be sure the root zones of azaleas & rhododendrons are thoroughly mulched. Any organic material will do, but mulches made from oak leaves, shredded oak bark, or pine needles are preferred.
•Living Christmas tree basics:
- dig the planting hole before the ground freezes.
- mulch and cover the backfill soil and the planting hole to keep them dry and unfrozen.
- don’t allow the tree’s roots to become dry
- spray with an anti-transpirant to reduce needle moisture loss.
- store the tree outdoors in a cool, shady, windless area until the last minute. Mulch the roots to prevent cold injury.
- set the tree up in your coolest room.
- don’t keep the tree indoors for more than one week. Plant outdoors promptly.
•Hairspray works well to keep seed heads and dried flowers intact on wreaths and arrangements.
•Hollies may be trimmed now and the prunings used in holiday decorations.
•Only female holly trees bear the colorful berries. There must be a male tree growing nearby for pollination, if fruits are desired.
•Christmas trees hold needles longer if you make a clean, fresh cut at the base and always keep the trunk standing in water.
Several of our favorite holiday plants should be kept from children and pets, yet often they pose no serious danger in small amounts. There are many other and more toxic substances to children in homes to be mindful of, especially cosmetics and personal care products.
The poinsettia (Euphorbia pulcherrima), the most popular flowering potted plant for indoors, has gotten a bum rap for a number of years. It’s been falsely accused of being poisonous, yet no deaths from this plant have ever been recorded. In fact, research studies at Ohio State University have proven that poinsettias present no health hazard.
The rumors arise from a highly questionable report of a single fatality in Hawaii more than 80 years ago, a child who reportedly died after eating one leaf. However, that doesn’t mean the poinsettia doesn’t have toxic properties. If ingested, it can irritate the mouth and stomach, sometimes resulting in diarrhea or vomiting.
The sap may cause a poison ivy-like blistering on contact with the skin on some persons unless washed off immediately. That’s why it’s important to place poinsettias, and other holiday plants, out of the reach of children and curious pets. Keep in mind that pets and people may differ in what plants are toxic, and to what degree.
How safe are other holiday plants? Here’s the rundown on plants with toxic properties.
Holly (Ilex): Branches are used during the holidays in arrangements for the shiny (but prickly) dark green leaves and berries. Eating the bright, red berries of this plant usually result in no toxicity in small quantities. Large quantities cause nausea, abdominal pain, or vomiting
Jerusalem Cherry (Solanum pseudocapsicum): This potted plant has been more popular in decades past, but still can be found during the holidays (so also called Christmas Cherry) for the rounded red fruits against the dark green leaves on a plant about a foot high.
Every part of this plant contains the toxic substance solanocapsine, especially in unripened fruits and leaves. Eating the fruit or foliage will adversely affect the heart and can cause a range of symptoms including stomach pain, vomiting, headache, drowsiness, to others more severe
Mistletoe (Phoradendron serotinum): This plant parasite of deciduous trees in the Southeastern states is used during the holidays for hanging above doorways, and for its white berries. While most exposures result in little or no toxicity, eating large amounts can cause acute stomach and intestinal disorders. These are caused by the chemical phoratoxin, related to ricin.
Yew (Taxus): The leaves, seeds (not the red fleshy covering), bark, and twigs of this evergreen can be toxic, causing breathing difficulties, uncontrollable trembling, and vomiting. Most reported poisonings are from the seeds, and only result in mild symptoms. Allergic reactions may occur from nibbling on leaves. Yew is a great example of the difference between people and animals, toxic to the former but devoured by deer.
Azalea (Rhododendron): This holiday plant is mainly grown as a shrub outdoors with thousands of variants. The leaves can be toxic, as is honey made from flower nectar, containing grayanotoxins. Perhaps the first written account of rhododendrons was from the 4th century in Greece depicting the poisoning of ten thousand soldiers from a yellow shrub azalea. Recently, one study concluded that eating moderate amounts of azalea posed little danger to humans. Pets and children may be more seriously affected, so should be kept from thes
Cyclamen (Cyclamen persicum): Since the thickened roots (rhizomes) of these are the toxic part, containing triterpenoid saponins, it is unlikely humans (including children) would eat such and be affected, and then only if large quantities are ingested. Pets, especially those that like to dig in pots, should be kept away from cyclamen.
Amaryllis (Hippeastrum): The toxic part of this plant is the bulb, which contains lycorine and similar alkaloids. These are the compounds found also in daffodils, and the reason wild animals like deer know to leave them alone. House pets may not be so wise, so keep these away from them. Ingestion by humans is unlikely, with small amounts producing few or no symptoms.
For more details on toxic plants of all types, including common houseplants, consult the second edition of the Handbook of Poisonous and Injurious Plants by doctors Nelson, Shih, and Balick. From Springer publishing, it is one of the most authoritative, up-to-date, and affordable such references for human poisoning by plants, and is used in many poison control centers.
December brings family and friends together to celebrate the holidays. Make sure you have a safe season by taking a few precautions before your guests arrive.
For starters, take care with holiday decorations, especially if your guest list includes young children or pets. Although poinsettias have proven not to be poisonous, they may cause internal upset if ingested. Contact with the sap may result in a skin rash. Other Yuletide plants like holly and mistletoe do have toxic properties, however, and consumption can lead to mild to acute stomach and intestinal disorders, so place these out of reach.
If you have a Christmas tree, anchor it to something sturdy like the wall or moldings with screw hooks and wire or fishing line to prevent disaster should a frightened cat or curious child attempt to climb it. Use a stand with a flat, broad base for extra stability. Hang favorite ornaments and breakables near the top of the tree along with dried flowers, pinecones, and wood ornaments that dogs and toddlers might find appealing.
A fresh tree can drink up to a quart of water a day–often more the first few days–so be sure to keep the stand filled to prevent the tree from drying out. Adding a tree preservative to the water will help. Place your tree away from heat sources like fireplaces and radiators, and make sure light cords aren’t cracked or frayed, a safety hazard.
If you ordered a floral centerpiece, or received one from a thoughtful guest, add water as soon as it arrives. The florist foam which holds the flowers in place needs to be kept very wet or else it will draw moisture from the flowers and hasten wilting.
Don’t just feel the foam block. Check the water level in the container, too. If possible, submerge the container and foam block in a sink full of water for an hour or so to get it thoroughly wet if not already so. Then check the water level daily and add water as needed.
If you receive cut flowers, use a sharp knife to recut the stems to allow better water absorption. Place the flowers into a container of 100-degree F water for 30 minutes. This is particularly important for roses, which may not open fully without this warm water treatment. (The water won’t stay at this temperature, of course, but the initial boost of warm water will help the flowers open.)
Arrange the flowers in a vase of cool water with floral preservative. To extend the life of the flowers add fresh water to the vase daily as needed and change the water every three days, recutting the stems as before. Place the arrangement in a cool spot at night.
Outdoors, keep your walkways safe for visitors by using kitty litter, sand, or environmentally safe salt to melt ice and early season snows. Place wooden teepees over shrubs and other foundation plantings to prevent snow falling off the roof from crushing these plants.
Going away for the holidays? If you can’t find a plant sitter, then check your local garden center for an auto watering device, which will provide your plants with water while you are away. These also are available online and through mail order.
By Dr. Leonard Perry
If you received a poinsettia, cyclamen, or other flowering plant for the holidays, there’s no need to throw it out with the Christmas tree. With proper care and feeding, these potted plants will continue to bloom for many weeks and may even bloom again next year.
Azaleas like it cool, wet (don’t overwater), and bright and will continue to bloom under these conditions. Feed monthly, using a fertilizer especially formulated for acid-loving plants. When flowers fade, snip off and pinch back the tips of the new shoots to promote compact, bushy growth.
Around June 1, repot in a mixture of equal parts peat moss and sand or soil. Add a heaping teaspoonful of bone meal or superphosphate. Bury the pot up to its rim in the garden. Water often and turn every few weeks to break off any roots growing through the drainage holes.
Before the first fall frost, move the plant indoors to a cool (45 to 50 degrees F nights), sunny room until buds begin to swell. Then move it into a warmer (60 degrees F nights) location to force flowering.
Poinsettias need good drainage, so if the pot is wrapped in foil, remove the foil or make a hole in the bottom so water can drain out. Water only when the soil surface is dry.
A common complaint about poinsettias is that they lose their leaves too quickly. This is a sign of poor growing conditions. Poinsettias need at least a half day of sun, a draft-free location, and night temperatures of about 65 degrees F.
To induce bloom next year, cut back the shoots by about one-third their length when the bracts (colored leaves) fade. This may be as late as July! Move the plant to a cool, well-ventilated spot. Water infrequently.
In late May place the plant in a sunny window. Water and fertilize regularly. Pinch back new growth. For eight weeks, beginning in mid-September, place your poinsettia plant in a dark closet or room each night and remove it in the morning. This will encourage it to bloom again next December.
The Christmas cactus responds well to short days and cool temperatures. It usually will bloom year after year if kept at 50 degrees F for several weeks each fall. Starting about mid-September, gradually reduce watering until buds set. Then keep soil constantly moist.
The amaryllis, with its stalk of colorful blooms, is another favorite holiday plant. After the flowers fade, cut the flower stalk to about two inches above the bulb. Place in a lighted area, water, and fertilize.
Next summer, place it outdoors, water and feed as needed. When the tops die down, bring it indoors again. For four weeks, keep at 70 degrees F. At the end of that time, water to encourage new stalks and blooms.
You can prolong the bloom of your cyclamen by keeping it cool and evenly moist. Too high temperatures, too little water, or too low light may cause leaves to yellow and drop.
Feed regularly with houseplant food according to the label. Cyclamen can be put outdoors over the summer. As with azaleas, after flowering keep the plant on the dry side a month or more, then repot.
Most people are only too aware of the damage and corrosive effects of salt on automobiles. On heavily traveled highways from 40 to 80 tons of salt per lane mile per year may be applied. Landowners along these roads also are aware of the damage to plants that such salt can cause.
Deicing salt is usually refined rock salt consisting of about 98.5 percent sodium chloride, 1.2 percent calcium sulfate, 0.1 percent magnesium chloride, and 0.2 percent rock. Calcium chloride is reported to be less toxic to plants but is seldom used because it is much more expensive than rock salt and more difficult to handle.
When sprayed onto plants from passing cars and plows, salt may enter plant cells or the spaces between the cells directly. One result of this “salt application” is that buds and small twigs of some plant species lose cold hardiness and are more likely to be killed by freezing.
Salt accumulation in the soil also may cause plant injury. This frequently occurs when salt-laden snow is plowed off streets and sidewalks onto adjacent lawns.
Anyone who has tried to get table salt out of a wet shaker knows how readily salt absorbs water. Rock salt exhibits the same property in the soil and absorbs much of the water that would normally be available to roots. Thus, even though soil moisture is plentiful, high amounts of salt can result in a drought-like environment for plants.
When salt dissolves in water, sodium and chloride ions separate and may then harm the plants. Chloride ions are readily absorbed by the roots, transported to the leaves, and accumulate there to toxic levels. It is these toxic levels that cause the characteristic marginal leaf scorch.
Measures to prevent or lessen injury from salt include using calcium chloride, where feasible, or using sand or cinders. Late season applications (after March 1) are most detrimental and should be avoided if possible since this is the time plants are coming out of dormancy and are most susceptible to injury.
