Early symptoms of leaf chlorosis and curling.
Photos courtesy of Margery Daughtrey of Cornell Cooperative Ext of Suffolk County NY.
The backbone of the shade gardener’s summer display has been Impatiens for as long as I’ve been gardening (which is longer than I’ll post in a public forum. But that long starring role has come to an abrupt halt this year due to the infamous, Downy mildew fungal like disease caused by the pathogen, Plasmopara obducens. The symptoms caused millions of gardeners to drag out their hoses in attempts to combat the disease, which mimicked the appearance of water starved plants.
This tremendous shake-up in the Horticultural industry has growers, breeders and chemists scrambling for solutions and workarounds. It is affecting this billion dollar industry in big and small ways at a time when our economy is struggling. The gardener goes to the nursery to place part of their closely budgeted money to bring a season of color and happiness to their home. The nursery is in a seasonally based business & feels the pressure of cultivating new customers into the Art of gardening as well as taking care of their established base of avid buyers.
Leaf drop symptoms on Impatiens walleriana caused by Plasmopara obducens or Downy Mildew. Photo courtesy of Margery Daughtrey of Cornell Cooperative Ext of Suffolk County NY
Under competitive pressure these nurseries offer their customers plant warranties. It boggles the mind how a seasonal small business would be able to sustain themselves when a calamity like the collapse of the stalwart impatiens plants would affect their bottom line once the warranties start rolling in.
One of the largest growers and breeders of Impatiens is right here on Long Island. Ivy Acres, located in Baiting Hollow, supplies a customer base not only on Long Island but also in New Jersey, Westchester County & Southwestern CT. They are the suppliers to the wholesale nurseries, so the chain of businesses affected continues up the chain of distribution.
What does that mean for us, the local gardener? What that means is that there is immense pressure to bring to market disease resistant replacements for the annual market geared to shade tolerant plants. For the next few years we will be seeing a tremendous array of new opportunities and options as replacement plants are introduced into the Horticultural market stream.
According to Mark Viette on his Sunday morning WOR radio show some suggested replacements for our dearly departed Impatiens walleriana at the moment are:
- New Guinea Impatiens
For more information on this new gardeners heartbreak visit the Cornell Cooperative Extension of Suffolk county and download their .pdf flyer titled “Impatiens Downy Mildew in The Landscape“
My garden doesn’t go into the winter season all tidy & neat. I enjoy seeing seed heads popping through the snow. The visual treat of shadows cast about by the wind, dancing along the walls seen from the windows of my warm home.
From my dining room window, the seed heads of tall grasses are seen swaying in the breeze with the floodlight of the pure winter sun behind them.
From the kitchen window the afternoon sun gleams through the slivers of peeling bark of the Acer griseum, wisely named Paperbark Maple. Tissue thin decorations provided by nature.
What a joy to watch teensy birds land on the seed stalks of last summer’s Echinacea, barely bending them. My winter garden provides them a smorgasbord of treats so they keep coming back for more. We have an agreement.
The evergreen stalwarts of my woodland garden, the hellebores & Polystichum acrostichoides (what a fabulous name for a Christmas fern), help to delineate the pathways once the snow has fallen. They’re markers keeping me on the right track. I need that help quite often.
The hellebores serve another important service. They are the harbingers of spring. As I enjoy the subtle visual treats of winter I can’t help but poke underneath their large leaves seeking hungrily the buds signaling the beginnings of a new season of visual excitement.
Chasmanthium latifolium. Northern Sea Oats gracing my winter garden
Deadheading the spent flowers on a rhododendron tends to focus the energy of the plant towards new flower production and general plant health. It also improves the sight of the plant when not in bloom.
To deadhead, use your fingers and gently rock the base of the spent flower truss back and forth until it separates from the plant. That’s it. Now you can either toss the spent bloom under the shrub for mulch or discard on the compost heap. Your fingers might get a bit sticky from the residue but that’s part of the fun of gardening.
I tend to deadhead my rhodi’s in the evening after I’ve worked all day in the garden and I’m strolling around to admire my work. I usually stop when it gets dark and that’s how I know it’s dinner time.
- After the blooms are spent it is beneficial to deadhead your rhododendron
NOTCHED LEAVES ARE CAUSED BY WEEVILS
Notched leaves on your rhododendrons are caused by a variety of species of weevils. The adult forms of the weevil tend to feed at night during the springtime when you’re resting after a hard day in the garden. The damage will not kill your plant, just cause unsightly notching on the leaves. Of course, the leaves being evergreen will be around awhile to annoy you.
- These notches on the Rhododendron leaf was caused by a weevil
• Hand pluck the critters.
One method of control is to go out to your garden in the evening with your flashlight and pluck the weevils from underneath the rhodi leaves and toss them into a bucket of water. This never appealed to me.
• Spray with systemic insecticide.
Another, more toxic method is to spray with a systemic insecticide, like Orthene. Make sure to follow the instructions on the label. Soak the leaves, both top and bottom as well as the soil underneath to get the best control.
• Accept imperfection.
The third method is to allow for a measure of acceptance of the notches and let nature take its course. Your neighbors will either respect your concern for the environment or talk about your lack of concern for aesthetics.
Generally speaking, cultural requirements are less “demanding” for lepidote (small-leaf) rhododendron and azaleas, both evergreen and deciduous. They tolerate, and to some extent require, more sun than elepidotes, and azaleas will also tolerate less well-drained soil. In all other respects, the general guidelines outlined above apply to all plants in this family. Site Selection Rhododendrons prefer a site that provides afternoon shade, some protection from wind, good drainage and air circulation. Sloping terrain is also … Continue reading →
Plectranthus and other members of the Lamiaceae family, like Coleus, are easy to propagate. These tender perennials are not hardy in my Zone 6 garden so before frost I bring in a few of my favorite plants as stock plants. If the plants are small enough I overwinter them in a pot with soil and towards the end of winter I begin propagation. If the plants are too big outside in the fall I proceed … Continue reading →
Repotting my meyer or foxtail asparagus fern, known in Latin as Asparagus densiflorus ‘Meyeri’, is a task I do every 5 years or so. I know it is time when there is no longer any room from the top of the soil to the top of the pot to hold water.
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Here is my Brugmansia suoveolens “Pink Beauty” in full bloom. So how did that white one slip in? In the morning the flowers are white but as the day moves on they turn pink. Very Cool! Well…one of the many things I like about my Brugmansia is that when the bloom first opens it is white and during the day the color gradually floods into this sensuous pink. Over time, as the blooms ripen they … Continue reading →
For years I’ve been hauling hoses back and forth across my property. Each year the hoses get heavier and more difficult to move. In the last few years I can count far too many lost additions to my garden for want of water. Not a good way to treat the plants and certainly not a good way to protect the investment I’ve made in my garden. So we half bit the bullet and had the … Continue reading →
Rhododendrons have such a great place in plant hunter’s history. Tales are still being told and re-enacted as new and old seekers traverse the back roads and non-roads of the Himalayas in search of the newest and rarest of Rhodies. Courage, stamina, and leeches always play a big role in these adventures. Having quite a different perspective of plant hunting, I traverse the hills and dales of Long Island in search of the ever elusive … Continue reading →