Archive for December, 2009

Ten Common Houseplant Problems

Monday, December 28th, 2009
David Deardorff

David Deardorff

We’ve prepared a list of the ten most common problems of houseplants. If you’re having a problem with a houseplant, it’s most likely going to be due to one of the following.

1. Overwatering.

More houseplants die from overwatering than from any other cause. Never let the pot sit in water in a saucer. Put marbles or pebbles in the saucer and set your pot on top of them to raise the pot up and away from the water in the saucer. Make sure the pot has adequate drainage holes. Allow soil to dry out in between watering. When you water, water the root zone of the plant, not the foliage.

This crown-of-thorns houseplant struggles to survive in a pot without drainage holes.

This crown-of-thorns houseplant struggles to survive in a pot without drainage holes.

2. Air is too dry.

Keep all your houseplants away from heat sources like heat registers, electric heaters, or radiators. Hot air blowing on a plant will quickly desiccate it. Mist plants to increase humidity, especially if you live in a dry climate. It also helps to place pots on shallow gravel filled trays of water.

Dry, brown, dead tissue shaped like an upside down V at the tips of the leaves tells you conditions are too dry for your plant.

Dry, brown, dead tissue shaped like an upside down V at the tips of the leaves tells you conditions are too dry for your plant.

3. Not enough light.

Put the right plant in the right place. Consult plant labels and packaging, and reliable books, magazines, and internet sites to determine a plant’s light requirements. Plants that need full sun rarely make good houseplants. Plants adapted to the low light levels of tropical forests do quite well in our homes.

4. Ambient (room) temperature too hot (especially at night).

The best houseplants are all tropical species that are able to tolerate the warm nighttime temperatures we keep in our homes. Temperate zone plants are often killed by warm nights because they burn up more fuel than they are able to make. That’s why miniature roses do not survive indoors, they starve to death. Turn the thermostat down, especially at night, to 60 degrees.

5. Pot bound.

If your plant sucks up all the water you give it and then wilts a short time later it’s probably pot bound. Up-pot the plant to a larger pot and add fresh soil. This way you give the plant a larger volume of soil to plumb for moisture. Alternatively, take the plant out of its pot, shave off an inch of roots and soil around the sides and bottom of the root ball, then put the plant back in its pot with fresh soil.

5. Temperature, humidity and/or light regime changes, as when the plant is moved.

Some plants, like Bougainvillea and weeping figs, drop most of their leaves when you move them to a new location. Make the change gradually, if possible, and give the plant extra nutrients and water to cope with the shock.

6. Not enough water.

Determine the right amount of water for the particular plant (read the tag or look it up). Some plants, like cactus and succulents, require very little water. Other plants will tolerate being constantly waterlogged. Most plants, however, fall somewhere in the middle. In general, allow the soil to dry out in between watering and mist plants to increase humidity. Make sure the plant is not pot bound.

Mealybugs on the underside of this Hoya look like fluffy wads of cotton.

Mealybugs on the underside of this Hoya look like fluffy wads of cotton.

7. Insect pests, such as fungus gnats, whiteflies, mealybugs, and scale insects.

Plants under stress are more susceptible to pests. Make sure you put the right plant in the right place to reduce stress. Give it the proper amount of light and water, the best temperature regime, and soil conditions to allow it to thrive and you’ll have fewer problems. Wherever possible, choose resistant cultivars and always inspect and quarantine plants when you first bring them home.

Mulch or top dress containers. This helps to control fungus gnats.

Sanitize. Remove and destroy insect infested leaves or stems.

Remove any pests you can capture, either with your hands or use a vacuum cleaner.

Physical barriers like sticky cards work well for adult whiteflies and fungus gnats.

Provide air movement with a fan set on low.

Make sure your windows and doors have screens to reduce the number of insects in the house.

Insecticidal soap sprayed directly onto the pests will kill them and is safe to use in your home.

Use rubbing alcohol on Q-tips to grub out mealybugs.

Drench the pot with Bt-i (Bacillus thuringiensis israelensis) for fungus gnats

Spray Neem oil to control most houseplant insect pests.

Horticultural oil (look for ones made from vegetable oil).

Pyrethrins made from botanical sources also work well.

8. Spider Mites.

This is a common problem under dry, dusty conditions. Mites are not insects, they’re related to spiders. They are very tiny and hard to see. They come in to your house on infested plants.

Quarantine new plants until you’re sure they’re mite free.

Sanitize. Remove badly infested leaves and discard them.

Blast leaves with water to wash mites away. Keep the leaves free of dust.

Misting the foliage discourages mites (they don’t like water).

Insecticidal soap sprayed directly on the pests will kill them.

Neem oil controls mites.

Horticultural oil (vegetable oil base) smothers mites and their eggs.

Sulfur is a natural element that mites don’t like.

Pyrethrins made from botanical sources also work.

This philodendron shows the watersoaking typical of bacterial infections on the leaves.

This philodendron shows the watersoaking typical of bacterial infections on the leaves.

9. Diseases, such as fungus and bacteria.

Sanitize. Pluck off infected leaves and put them in the garbage. Do not compost.

Mulch. Top dress containers to reduce splash up from the soil to the leaves.

Provide air movement with a fan set on low. Don’t crowd plants. Put the right plant in the right place. Choose resistant cultivars and keep the foliage dry when watering.

A simple spray made from baking soda prevents fungal spores from germinating.

Sulfur sprayed onto the foliage also prevents fungal spores from germinating.

Copper sprayed on the leaves will kill bacterial pathogens.

Bacterial fungicide (Bacillus subtilis) is a living bacterial culture which kills fungi.

Neem (has a strong odor for some people) Keep it away from aquaria.

10. Nutrient deficiencies.

Start with a good quality potting soil, an artificial mix that contains perlite, vermiculite, and other materials that create space and air pockets, yet retain water. Some plants, such as orchids or cactus, need special mixes. Never use garden soil in a container because it will become very compacted over time. Use a good organic fertilizer whenever possible.

Happy Holidays

Friday, December 25th, 2009
Kathryn Wadsworth

Kathryn Wadsworth

Today is Christmas day and I thought I’d share with you a few photos of some of my favorite native plants of the Northwest. All of the plants featured here are evergreen shrubs or trees. All of them produce berries that attract birds to your garden. All the fruits are edible by us humans too and are quite tasty.

David and I went out for a walk on Christmas eve and took these photos to share with you. We walked along the shores of Hood Canal on the Kitsap Peninsula up in Washington State. Winters are mild here and there is no snow on the ground. Plants that keep their leaves all winter are especially valued in the landscape in the Northwest.

The Olympic Mountains form a spectacular backdrop to this scene of Hood Canal

The Olympic Mountains form a spectacular backdrop to this scene of Hood Canal

Evergreen huckleberry (<i>Vaccinium ovatum</i>) has very pretty evergreen foliage. Its berries are small, black, and extremely tasty.

Evergreen huckleberry (Vaccinium ovatum) has very pretty evergreen foliage. Its berries are small, black, and extremely tasty.

Oregon grape (<i>Mahonia aquifolium</i>) carries its shiny compound leaves all year long. Yellow flowers in spring become blue berries by the end of summer. The tart berries make excellent jams and jellies.

Oregon grape (Mahonia aquifolium) carries its shiny compound leaves all year long. Yellow flowers in spring become blue berries by the end of summer. The tart berries make excellent jams and jellies.

Leaves of salal (<i>Gaultheria shallon</i>), called "lemon leaf" by florists, find wide commercial use in bouquets. This plant also makes very tasty berries, sweet and juicy.

Leaves of salal (Gaultheria shallon), called "lemon leaf" by florists, find wide commercial use in bouquets. This plant also makes very tasty berries, sweet and juicy.

The Holly and the Ivy . . .and Mistletoe too.

Monday, December 21st, 2009
David Deardorff

David Deardorff

‘Tis the time of year when I find myself standing under a sprig of mistletoe expecting to be kissed! We’re putting branches of bright green holly with brilliant red berries in bouquets and wreaths to decorate the house for the holidays. And I see out the window, in the snow, that the ivy is in full bloom. What a crazy plant, to burst into bloom in winter.

The ivy featured in the carols and cultural traditions of Great Britain and Northern Europe is the English ivy, Hedera helix. It is in full bloom at the moment, covering itself with silver dollar sized umbels of small, inconspicuous flowers. No wonder the ancients regarded this plant with awe – it flowers in winter. Today, in the Pacific Northwest, we also regard it with awe, as a noxious weed! Each small flower will mature into a pea-sized, black-purple berry in spring. Birds love these berries and spread the seeds of this plant far and wide. The seeds survive passage through the gut of a bird to be pooped out in a new location.

Curiously, English ivy flowers in winter when few other plants bloom.

Curiously, English ivy flowers in winter when few other plants bloom.

English ivy’s long juvenile period lasts ten to thirty years. The juvenile plants are the familiar ornamental vines with the palmately-lobed leaves available in numerous named cultivars. Eventually the plant becomes sexually mature. It flowers, makes seeds, and changes its growth habit. Its a vine with long flexible stems as a juvenile, but a shrub with short, stiff stems at maturity.

The bright green leaves and brilliant red berries of English holly are widely used for decoration during the winter holiday season.

The bright green leaves and brilliant red berries of English holly are widely used for decoration during the winter holiday season.

The holly featured in Christmas carols is the English holly, Ilex aquifolium. The stiff leaves of this plant are heavily armed with spines around the edges. The bright green leaves contrast nicely with the bright red berries on the female plants. Male plants, of course, have no berries. This plant, like the English ivy, is another invasive species in the Pacific Northwest. Birds eat the berries and spread the seeds.

The holiday mistletoe of legend, Viscum album, unlike the previous two plants, is a parasite. It comes from Northern Europe and Great Britain where it grows on tree branches and sends its specialized roots (haustoria) down into the tissues of its host to steal water, food, and mineral nutrients (much like a tapeworm in animals). Female mistletoes bear berries, which are white, and the seeds are spread by birds. Mistletoe has green leaves and is able to manufacture some of its food by photosynthesis, but it has to get all of its water and mineral nutrients from its host. Tradition dictates that you will get kissed if you stand under mistletoe so hang it above doorways or other places people use frequently.

In the USA, the holiday mistletoe from Europe has escaped into the wild in California. California also has native species of mistletoe in a completely different genus (Phoradendron). These parasites are easily spotted in winter when they show up as leafy green balls on the leafless branches of their host trees. Healthy trees can stand a few of these parasites, but a large number of them can kill your tree. The best way to deal with them is to prune them away by cutting off the infected branches.

Native mistletoe on white oak in Southern Oregon.

Native mistletoe on white oak in Southern Oregon.

Today is December 21, the Winter Solstice. Tonight is the longest night of the year in the northern hemisphere. This is the turning point, the time when the solar cycle begins to turn toward the light and the days begin to get longer. Solstice is, of course, cause for celebration, and many cultural traditions call for mistletoe over doorways, and holly and ivy around the fireplace.

In ancient times it was extremely important to know when the winter solstice, the moment of the sun’s rebirth, would occur. Communities needed to ration their food supplies in order to survive the famine months of winter. Stonehenge, for example, is a giant calendar that specifically marks the winter and summer solstices. Built nearly five thousand years ago as an astronomical observatory, it stands today as testament to its usefulness to the people who built it.

To the ancients, plants that kept their green leaves through the harshest winter storms, the holly, ivy, and mistletoe, must have seemed mysterious and magical. These plants were often considered sacred. People cut sprigs, bring them into their homes, and have done so for thousands of years. We do so to celebrate midwinter festivals, traditions to continue various pagan and Christian festivities. At our house, Kathryn and I bring the holly and the ivy into our home . . . and mistletoe too. We love to celebrate the turning of the wheel, the eternal cycles of nature. And we like kissing too!

Noble Fir and the Return of the Light

Friday, December 18th, 2009
Kathryn Wadsworth

Kathryn Wadsworth

White puffs of breath hang in the cold air. Snow dusts our heads and shoulders as we brush back the limbs of conifers that crowd the trail. David and I hike the Larch Mountain Trail near the Columbia River, east of Portland. We’re not going far on this wintry day, hoping only to catch a glimpse of noble fir, Abies procera, in its native habitat.

As we near the holiday season, we’re seeking a “wild Christmas tree.” David decided we should look for the “perfect” wild Christmas tree, the noble fir. “The most elegant of Christmas trees,” he says. “It holds its branches symmetrically, the boughs sturdy and level.” He extends his arms straight out, away from his body.

“It twists its needles upward, exposing the lower surface of the stem. A perfect place to hang ornaments. The needles have a bluish cast and the tree does not shed them as they dry. Yep, just about perfect.” He continues with long strides up the path.

Larch Mountain, where noble fir is abundant, is the best location for our wild tree safari. We might even find a 200 foot specimen of this peerless winter holiday tree. Despite the mountain’s misleading name, it harbors no larch. Both mountain and trail get their names from timber men who harvested and sold the noble fir as larch. No one would buy fir in those days.

David leads the way to the right micro-climate: mid-elevation, a moist habitat, and rich deep soil.
“Here’s one,” I cry out in order to get his attention.

Native noble firs dominate a ridge top.

Native noble firs dominate a ridge top.

He stops and shakes snow from the bough. “Almost,” he says. “This is a Douglas fir, not a true fir.” He turns a branchlet over to expose the growth habit of the needles on the underside. “In noble fir, the needles look like little hockey sticks. See, these needles grow straight out from the stem all the way around, like a bottle-brush. But, on noble fir, the needles bend, right at the base.”

“Why?” I find these details endlessly fascinating.

“An adaptation to garner more light. So, it makes more food, can out-compete its neighbors,” David says. “Also, look at the bud at the tip of the branch. It’s pointed. On true firs the bud is round.”

“Well, this tree is pretty too.” I head up the trail.
“Sure it is. And, at least, you recognized the differences among firs, pines and spruce.” David catches up, then retakes the lead.
Earlier he explained distinctions in the world of conifers. Pine needles occur in bundles of two, three, or five. Fir needles are solitary and spruce needles bite. In other words, they’re sharp and, well . . . needle-like. But that tidbit of information is irrelevant; there is no spruce up here.

“Whose idea was this?” I grumble, rubbing my hands together. I’m not used to this weather despite living in the Pacific Northwest for some years.

David laughs. “C’mon, where’s your Christmas spirit?”

I laugh along with him. But I am thinking about the idea of bringing trees into the house in mid-winter. I mean, whose idea was this? I know the Egyptians were the first. They brought date palm fronds inside during winter solstice celebrations. But does that count?

All the mid-winter festivals celebrate the shortest day of the year in some way. It marks the return of the light. The point when the sun begins to climb back up, higher in the sky, bringing longer days. That’s the moment when you know that the long dark months are over. It’s the return of hope.

Still, who started the tradition of bringing an evergreen tree into the house? I know the earliest written record comes from Alsace. A forest ordinance of 1561 reads, ‘No burgher shall have for Christmas more than one bush of no more than eight shoe lengths’. That sounds like the first environmental regulation to me.

A Hessian mercenary soldier fighting with the British probably put up the first Christmas tree in North America in 1777. Yet the tradition of having a decorated tree inside most certainly came to this country with German immigrants. Matthew Zahn of Lancaster, Pennsylvania wrote about his family’s excursion to cut a Christmas tree on December 20, 1821. The tree was decorated with nuts, dried fruits, and seeds.

The English colonists actually outlawed Christmas trees. The idea really wasn’t acceptable until Queen Victoria and Prince Albert popularized it in the 1840s. In fact, Massachusetts banned their use until 1857.

Noble fir boughs are strong and beautiful.

Noble fir boughs are strong and beautiful.

In my musing I have lost sight of David, but soon hear his whistle and I hurry to catch up. Two more bends in the trail and I find him examining the silvery-blue foliage of a young noble fir.

“See the hockey sticks?” David holds a bough in a gloved hand. He hands it to me. “Feel the weight of it. Smell it.”

“It’s heavy.” I hold it to my nose and take a long, deep breath. “It smells like the deep forest.”

“And like Christmas,” David adds.

Choosing Holiday Trees

Monday, December 14th, 2009

Choosing Holiday Trees

David Deardorff

David Deardorff

Bringing a tree into your home to celebrate the holidays is a tradition that comes to us from ancient times. For many centuries before the birth of Jesus, pagans celebrated the winter solstice by bringing boughs of evergreen trees into their homes and decorating them. In the 1850’s Christians in America began to adopt the practice amidst great controversy. But no matter what your religious philosophy, whether you’re celebrating Solstice, Christmas, Hanukkah, or Kwanzaa, bringing a tree into your home in the middle of winter is a pleasant thing to do. It symbolizes the return of the light and the promise of renewal in the spring, and that’s a good thing.

Large houseplants like palms can make excellent holiday trees.

Large houseplants like palms can make excellent holiday trees.

There are so many choices, how do you decide which kind of tree you want to bring into your home? Kathryn and I are oddballs in that respect because for many years we had a lovely old weeping fig tree (Ficus benjamina) in our living room. Through most of the year she was simply a houseplant. But on the winter solstice we transformed her by dressing her with lights, ornaments, and tinsel so she became a glorious holiday tree for a couple of weeks.

Any large houseplant, palms or dracaenas for example, can be used for a holiday tree. Many people use a potted Norfolk Island pine (Araucaria excelsa) in the same way. Still, cold-hardy conifers are the tree of choice for many, especially a live tree versus a cut one.

Choosing a live tree is an excellent idea because you can plant the tree in your yard after the holidays. A conifer is prepared with its root ball carefully wrapped in burlap, what the nursery will call balled and burlapped, or B&B. The root ball is muddy so set it into a tub or wrap it in plastic before you put it on the living room floor. Do not keep a live conifer in your home longer than two weeks. Our houses are too warm and a living coniferous tree will suffer. Right after the holidays take the tree outside into the cold. Bury the root ball in mulch like bark, or straw, to keep it healthy until the ground is thawed out enough for you to plant it.

I recommend the Douglas fir, Pseudotsuga menziesii, a popular choice in every region of the country and very widely grown on Christmas-tree farms. It is frequently sheared into perfect pyramidal shapes. Douglas fir has a sweet scent and holds onto its needles as a cut tree. It is also available as a living tree. Even though Douglas fir is called a fir, it isn’t really a true fir. Its cones hang down and have three-pronged bracts sticking out between the cone scales.

True firs (Abies) have cones that stand up straight and lack the odd three-pronged bracts. I highly recommend any of the true firs both as living and as cut trees. Some of the most popular Christmas trees in the country region by region are firs. The Fraser fir (Abies fraseri) is popular in the South, the balsam fir (Abies balsamea) in the Northeast, white fir (Abies concolor) in California, and noble fir (Abies procera) in the Pacific Northwest. All these firs are pleasantly scented, hold onto their needles well as cut trees, and have stout branches which tolerate heavy ornaments. Many of them are also available as live trees, balled and burlapped, to plant in your yard after the holidays.

Another highly recommended living holiday tree is the Colorado blue spruce (Picea pungens). The white spruce (Picea glauca) is less widely used than its blue cousin, possibly because it reportedly smells bad. Spruces are not the best choice as cut trees because they tend to drop their needles, but as balled and burlapped live trees they are very good choices and will retain their needles. Remember, you can’t keep it in your home longer than two weeks.

Pines, of course, are also good holiday trees, but not as frequently used as the ones mentioned above. These include the Scotch pine (Pinus sylvestris), the eastern white pine (Pinus strobus), and the Virginia pine (Pinus virginiana). These pines are generally less aromatic than Douglas fir or the true firs and appeal to those allergic to resinous scents. They hold their needles well but often have rather flexible branches that bend under the weight of ornaments. Many pines are available as cut trees and as living trees.

Another nice thing about using a living tree for the holidays is that, after you plant it out in the yard, you’ll have an outdoor tree to decorate. It will be available to you every year for many years to come.

Wild Houseplants, Part I

Friday, December 11th, 2009
Kathryn Wadsworth

Kathryn Wadsworth

When I was a kid my mother grew an enormous poinsettia (Euphorbia pulcherrima) in a dormer window in my bedroom. She had received it one Christmas as a small potted plant to decorate the dinner table. We always gathered as a very large extended “family” that included close friends of my parents and their children. My siblings and I are still friends with the children of these families and consider them hanai brothers and sisters. Hanai is a Hawaiian word that loosely equates to “adopted”. Holiday gatherings of our hanai family brought many celebratory traditions together: Jewish, Egyptian, German, and Celtic. I’m not sure who brought the little poinsettia as a gift, because all those cultures embrace the practice of bringing greenery and plants into our homes in winter, especially during the winter feasts.
Most of the time, the plant lived in a giant yellow pot in the bay window of my bedroom. There, it soaked up plenty of sunlight, just enough water, and not too many nutrients. To tell the truth, I never really paid attention to how my mother cared for it. But she must have babied that plant, because by the time I was a teenager, the poinsettia was lush, robust, and six feet tall.
Every autumn my mother came to my bedroom each evening and dragged that heavy pot and plant into my closet. Shoving the shrub among my clothes, she’d pull on the sting to turn out the light, shut the closet door, and forbid me to open it until morning. And by Christmas every year bright red “flowers” festooned the branches. I didn’t know then what I know now – that these are not really flowers, but modified leaves that change colors through the lengthening dark nights of early winter. Before the solstice and the return of the light.

Green flower buds and bright red bracts on my mother's poinsettia.

Green flower buds and bright red bracts on my mother's poinsettia.

The English common name comes from Joel Roberts Poinsett, who introduced the plant to the U.S. in 1825, when he served as the first U.S. Minister to Mexico. Poinsettias are large shrubs or small trees and are native to dry topical forests in Mexico, but now grow wild nearly everywhere in the tropics. Indigenous peoples have used their bracts to make red dye and their milky sap for medicine to reduce fevers.
I vividly recall the day I first saw a poinsettia in the wild. I was nineteen and had traveled to Belize and Guatemala with two college chums. We hitch-hiked from Belize City to Tikal and Guatemala City; we cadged a ride on a sail boat to the barrier islands off the coast; and we traipsed through the forest in search of adventure.
One night we camped in a clearing at the foot of one of the excavated pyramids at Tikal. In utter darkness, surrounded by the shuffling, calling, scurrying sounds of nocturnal animals, we threw our sleeping bags on the ground and slept the sleep of complete ignorance. The kind of ignorance that brings forth the guardian angels. Next morning we rose early and encouraged each other to climb to the top of the tallest pyramid. The real reason we were up at dawn is because the ants had emerged from their burrows and swarmed over us. They had a wicked bite.
We headed down the jungle trail, quickly leaving the clearing behind. In just a few feet we crossed paths with a long line of harvester ants – ones that cut leaves into little pieces and transport them over well-worn trails to feed their cultivated mushrooms. None of us knew much ecology then, so after watching them for a bit,  we dubbed them umbrella ants, and set off on our way again.
A troop of howler monkeys soon spotted us, and remaining at a safe distance, paralleled our track. Hooting and howling, they taunted us with their calls. One, who seemed to be an adolescent like us, swung aggressively close overhead, and tried to nail us with a torrent of his urine. That will teach us to trespass in his territory. Luckily he missed.

A wild poinsettia in Belize.

A wild poinsettia in Belize.


Just as we reached the base of the towering monument, I spotted a vaguely familiar shrub – leggy, and scraggly, yet similar to my old room-mate. A few reddish-pink bracts adorned its branches. I was completely taken aback. It was like running into an old acquaintance from elementary school – you know you know them, but haven’t been in touch for a long time. Suddenly I saw, really saw the plants of the jungle around me. Wasn’t that vine climbing up the trunk of that big tree just like the plant in my mother’s sun room? And what about the tree itself – wasn’t it a huge specimen of the small potted “fig” tree my mom had?
This was my first conscious encounter with a wild houseplant. Oh, to be nineteen again. To discover the world as if you are the first person to ever see such sights.

Poinsettias

Monday, December 7th, 2009

Holiday Flowering Houseplants: Poinsettia

David Deardorff

David Deardorff

It’s December and every time you go shopping – at department stores, grocery stores, big box stores, garden centers – you see poinsettias in full bloom. They make delightful holiday decorations because winter is their natural flowering time. The bright red “flowers” and bright green leaves say Christmas for many people. I put “flowers” in quotes because those big, showy, red “petals” are bracts, modified leaves, not flowers. The real flowers are tiny and insignificant.
In addition to several shades of red, poinsettias now come in an array of colors: white, yellowish, pink, and striped. There are also double-bracted varieties which have a larger number of colorful bracts than the original wild type.

The poinsettia makes a beautiful flowering houseplant for the holidays.

The poinsettia makes a beautiful flowering houseplant for the holidays.

The poinsettia, Euphorbia pulcherrima, is a tropical shrub, originally from Mexico. It adapts fairly well to conditions inside our homes. Put them on a bright, sunny windowsill because they need sunlight to grow well and stay healthy. They can temporarily live in a shady location when you use them for decoration, but put them back in the window. Don’t keep the pot in a saucer full of water because if the roots are constantly wet they’ll get root rot and die. If you live in a mild winter climate you can plant them outdoors in spring. Outdoors they get big, sometimes ten feet tall and six feet wide. Spectacular in full bloom. Remember, hard freezes will kill them.
As houseplants though, the biggest problem poinsettias face is whitefly. Whitefly is a tiny insect that flies up in your face when you disturb the plant. Generally they hide on the underside of leaves where they quietly suck sap out of your plant’s veins. Often, you don’t even notice them until you start to see sticky, glossy honeydew (a euphemism for insect poop) coating the leaves. There can be quite a lot of these insects on your plants before you’re really aware of them. You’ll notice them when you disturb your plant they fly about like a cloud of snowflakes.

A serious infestation of whitefly on the leaf underside.

A serious infestation of whitefly on the leaf underside.

Whitefly comes into your home, usually, on infested plants. In mild-winter climates they live outdoors and can come in through open windows or doors. But most often they arrive unseen on plants that were already infested when you bought them. These sneaky little devils get past you because you can’t see their eggs or their babies. You can only see the adults. The babies are microscopic crawlers lurking on the underside of leaves. After the plants are in your home for a few days you might begin to see some adults flying about when you water your plants.
If whitefly shows up on your poinsettias there are several good, non-toxic ways of dealing with them. Don’t automatically reach for a spray can. Remember, these plants are living in your home with you so be careful what you treat them with. It can be extremely satisfying to nail the adults by sucking them into your vacuum cleaner as they try to escape! Whiteflies are weak flyers and a fan will blow them away from your plants. They are attracted to yellow sticky cards — cards covered with goo that traps the insects when they land on it. Trapping and destroying the adults feels good because you feel like you’ve actually accomplished something.     But, until you deal with all the babies, these little buggers will be around to haunt you for a long time! Spray the undersides of the leaves with insecticidal soap to kill the crawlers and treat the plants with it every three days. Neem oil, used in the same way, will also work. Both these products are safe to use inside your home but Neem smells bad to some people. With whitefly under control you can keep your poinsettias year after year.

People Are Talking

Saturday, December 5th, 2009

What people are saying about our book at about.com. Read the whole review. The Bottom Line What’s Wrong With My Plant? (And How Do I Fix It?) is a book that every gardener, whether you’re a newbie or an old pro, should have on the shelf. It’s like having a Master Gardener at your beck and call, twenty four hours a day, seven days a week, any season of the year.

Orchid Obsession

Friday, December 4th, 2009

Orchid Obsession

Kathryn Wadsworth

Kathryn Wadsworth

David has turned his attention to the tropical plants that live in our houses, in particular one of his true loves – orchids.
My first day in Hawaii, many years ago, was filled with orchids. I had stopped to visit David on my way from Australia where I had been leading an eco-tour of the Great Barrier Reef. He lived in a tiny cabin deep in the jungle of the west Maui Mountains, where he headed up a research project in biomass production from tropical trees. A shimmering green light bathed the interior of his dilapidated shack. One of the three or four intact buildings of an abandoned poi factory complex. Of course, I loved it on sight. Surrounded by huge trees — mango, grapefruit, avocado, and monkey-pod — each with its own community of epiphytic orchids and ferns clinging to each massive limb. While I knew none of these plants were native, I was still enchanted.

A gorgeous member of the Cattleya alliance, Laeliocattleya Irene Finney blooms in spring.

A gorgeous member of the Cattleya alliance, Laeliocattleya Irene Finney blooms in spring.

We dropped off my luggage and rushed straight back to town to buy me an appropriate dress for the annual banquet of the Lahaina Orchid Society. In his spare time, David had become an orchid judge and breeder. Hundreds of guests mingled and merged, ebbing and flowing around me. Long tables filled the ballroom, each table festooned with orchid plants – all in magnificent bloom. The heady scent of orchid blossoms filled the air. I listened to bizarre conversations around me.
“Did you see that Ports of Paradise ‘Glenyries Green Giant’?’
“Oh yes, he da kine li’ dat.”
“I no know. What about that Ida Fukumura?”
“Yeah, she really da kine.”
Later I would learn that the first is an intergeneric cattleya hybrid and the second a phalaenopsis, but that night I sat stupefied as the mix of pidgin and orchid-speak assailed my ears. It was like listening to aliens from another planet trying to include me in the conversation. I smiled a lot.

Phalaenopsis Ida Fukumura flowers are large and intensely colored.

Phalaenopsis Ida Fukumura flowers are large and intensely colored.

Many remarkable events took place over the next few weeks of my visit. David took me to orchid shows and orchid ranges (what the rest of us might call nurseries). We visited other judges and experts, all of whom were smitten with orchids, afflicted with orchid obsession.

Paphiopedilums, or lady slippers, are one of the best orchids to grow as houseplants.

Paphiopedilums, or lady slippers, are one of the best orchids to grow as houseplants.

I gradually learned to distinguish between a cattleya and a phalaenopsis. Slowly I could recognize a dendrobium, a vanda, and a paphiopedilum. The orchid maniacs I met were mostly big men with arms covered in tattoos. Men who could easily be mistaken for the goons that gangsters send to break kneecaps. They showed me how to gently remove pollen from the “father” (pollen parent) and place it on the stigma of the “mother” flower (pod parent). With a toothpick!

The flowers of Vanda coerulea are spectacular in size and color.

The flowers of Vanda coerulea are spectacular in size and color.

David showed me his research – volumes of notebooks with orchid genealogies going back centuries in some cases. Research designed to support the breeding program he intended to start. We began touring orchid ranges in earnest with the goal of purchasing “stud” plants – those perfect plants, with the perfect genetic composition for David to use to create award-winning plants. Yes, David had it bad – a serious case of orchid fever. Yet, it never seemed extraordinary to me. It seemed perfectly normal, in fact.

Dendrobiums, like this Jaqueline Thomas, provide long-lasting cut flowers for bouquets.

Dendrobiums, like this Jaqueline Thomas, provide long-lasting cut flowers for bouquets.

We grew orchids in pots, on benches or on the ground beneath the towering trees surrounding the cabin. We borrowed a friend’s laboratory to sow orchid seeds in a sterile environment in specially prepared media inside glass flasks and baby-food jars. I read every orchid book, magazine and research paper David handed me. And the few weeks visit turned into months.
Without quite realizing it, the orchid obsession took over. We moved to the Big Island of Hawaii. We started our own orchid range. Built our own laboratory. Amassed a stunning collection of “stud” plants. We filled every inch of our lives with the incredible beauty of these exotic, luscious plants. Oh, and while we were at it, we got married.
Even though we no longer grow orchids, our love for these plants remains. I do not know why some people succumb – as we did – to orchid fever, but I highly recommend it. I guess for me orchids embody an incredible, wild, effortless ride into joy.

More Great Reviews

Tuesday, December 1st, 2009

Every day we get more fantastic reviews of our book and so many people are finding that our book is the perfect Christmas gift for all their gardening friends.

Here’s a link to a review on In the Garden Online so you can check out what people are saying about our book.

And another appeared in the Akron Beacon Journal.

And here’s a third at the Daily Botanical.