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Rhododendron and |
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Dear Dr. Rhody...bugs on seedlings? |
I was present at your presentation on growing rhododendrons from seed during the 2001 Eugene Convention. I ordered seed from the seed exchange and began to grow seedlings. The first year everything grew fine and had no problems. This year have noticed many, many little gnat-like bugs crawling all over the containers of seedlings and flying around the area. Are these bugs a problem? Will they damage my seedlings? - Fellow Grower |
Dr. Rhody responses: |
Dear Fellow Grower...Indeed, you have a problem! Fungus gnats are what you are describing. They are a major pest. Although they appear small and harmless...they can destroy your seedlings. |
fungus gnats... |
Fungus gnats eat the root of small seedlings. Unfortunately, I learned the hard way. I grew seedlings for several years and had good success. The year I ordered and planted some very unusual and hard-to-find species selections, I lost over half of what I planted...thanks to the fungus gnats. I almost gave up growing seeds. |
there's hope... |
There is hope! Some steps you can take to reduce your problem. Sticky yellow tags are a good trap and a good indicator of fungus gnats. I believe...not everyone will agree...peat moss contributes to the proliferation of fungus gnats. I think the gnats really love peat moss. Moisture is also a factor which encourages fungus gnats...and, of course, moss and fungus help, too. I am better able to control these variables with coconut fiber. It works for me. |
some chemicals will work... |
In order to eradicate fungus gnats there are a variety of chemicals that will help. Dursban will help kill adults, if you choose to use it. Gnatarol is a product that is very safe...but you have to use it very frequently. Cleanliness in your seed room can also help to cut down on gnats. There also are some new insect growth regulators available that will work...if you are certified to use them. |
be vigilant... |
Be vigilant...get rid of the gnats...and your seedlings will grow to become beautiful rhododendrons some day! |
Rhododendron garden tips...
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Here are a few suggestions from the North Island rhodo experts on how to be successful in your garden:
Some of the points above may not match the calendar...but they are worth taking note of...and you still may want to use some. Good Luck! |
Bug-busting tips |
Jerry Baker, a Master Gardener, has given the world wonderful tips on gardening and shows us again some things we should look for in our garden...and how to correct them. When strolling through your flowerbeds and gardens, it is important you keep your eyes open for insects. Here are my tried and true bug-busting tips that will keep those wiggling and winged warriors away from your annuals, perennials, and flowering shrubs. |
garden thugs are bullies... |
That's right...they always pick on plants that are weaklings. So fight bugs the best way...with a good, preventative maintenance program. Give your plants plenty of sunlight and water...feed them well...and weed them regularly. Healthy plants will be able to fight off most bugs without any additional help. |
aphids... |
Aphids like the cool, dark undersides of leaves. Shake them up! Let there be light! Lay pieces of aluminum foil under affected plants. Aphids are confused by increased light...and leave the leaves. Also, cut up two or three garlic cloves...and sprinkle them among your rose bushes to keep the aphids away. |
earwigs...use soy sauce... |
These guys like to nibble on the foliage and flowers of many plants...especially dahlias, zinnias, and hollyhock. To keep these ugly thugs from calling your yard home, you need to remove their hiding places. Any place that is dark and cool during the day is an ideal spot for them. Trap them...by putting an inch of soy sauce in the bottom of an old sour cream container, then top it off with a thin film of vegetable oil. Put the cover on...punch 3 holes near the top of the container...set it in your garden. Throw it out whenever it is brimming with bugs! |
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Autumn calls for gardening tips |
Fall is around the corner and it is a great time to plant those rhododendrons and azaleas that were not attended to this spring. The plants will concentrate on producing their root system instead of creating flowers...and they will not be subjected to the high temperatures and dry periods associated with the stresses of summer. Here are some things to think about as you prepare for fall...followed by winter.
With cooler weather upon us, I feel more energized and with shovel in hand, I am ready to tackle planting and transplanting a few shrubs. Remember to consider in years to come...just like children they outgrow their clothes and require room to grow! Happy gardening, |
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MORE and more Fall advice |
Now that the days are getting short...the rhodies will start going dormant. These are some more things to think about...and repeats from other rhody experts. Because the instructions are repeated and repeated...almost to the stage of rote...the instructions should become cemented in our day-to-day activities at this time of the year. Bill Stipe of Whidbey Island Chapter drives home the guidelines again!
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Leaves can tell the temperature! |
Garth Wedemire from the Fraser South Chapter has done a little research on why rhododendron leaves...curl and droop. Here are his findings. Most interesting. |
curl and droop is normal... |
Leaf curl and droop is normal when rhododendrons are exposed to extreme heat, extreme cold, or drought. It is a natural reaction that helps prevent dehydration under these conditions of extreme stress. The curl and droop should go away when the extreme condition is reversed. |
curling defense in cold weather... |
Leaf curling in cold weather is a defense against moisture loss through the leaf surface. When the temperature drops below 35°F, rhododendron leaves begin to cup and curl at the edges. At 25°F, the leaves have curled so tight that half the leaf surface has disappeared and the leaves droop. When temperatures hit the teens, leaves shrivel even tighter...turn brownish-green and dangle like stiff string beans. |
curl in summer... |
Rhododendron leaves curl and droop during the summer months...if they lose too much water, just as other plants wilt. The pores through which the plant loses water and takes up air are located on the underside of the leaves. When the leaves curl, these pores are protected, and the evaporation of additional water is reduced. The curled leaves protect the rhododendron plant from more water loss. |
a few facts... |
Leaves of rhododendrons respond to cold by first drooping...then curling up.
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leaf curling…a strategy... |
Leaf curling is a strategy to prevent moisture loss in the leaf tissue. As the temperature rises above freezing again...the leaves unfurl and look striking in the winter garden. Perhaps, a scientific study which investigates the relationship between curling and drooping...and temperature for various rhododendrons could be undertaken by researchers. |
not all rhodies curl and droop... |
Not all rhododendrons exhibit this ability to curl and droop. Some like 'Unique' do not respond as dramatically as others, like 'Crest'. When it gets very cold, 'Crest' curls its leaves up so tightly that they look like thin pencils. By looking out a window on a winter day, one can determine roughly how cold it is by the degree rhododendron leaves have curled and drop. When temperatures rise, the leaves open again. Next time you encounter a rhododendron, estimate the temperature by evaluating the curl of its leaves. You may surprise yourself with the plant's accuracy. |
Fall for Rhododendrons |
Norman Todd, Victoria Chapter, is a true-died devotee of rhododendrons...and he loves to write and write everything possible. Someone has unearthed a splendid article he wrote in the 1990s! The news editor of the Victoria's Chapter has searched the archives and the article appeared in the October 2007 newsletter...stating it was both "timeless and timely". Now, it is brought to your attention...for the fall of 2007. In the gardens of coast British Columbia the best time to plant broad leaf shrubs and trees is the fall. In October and November, the soil is still warm, the autumn rains have begun, and conditions are the best for the development of new roots. By planting in the fall, plants will become established before the burgeoning demands of spring signal the roots to send more nutrients for swelling blossoms and expanding leaves. |
unseen activity goes on... |
As long as the ground is not frozen, the roots of the broad leaf evergreens are purposefully working. To the human eye there does not seems to be much going on above soil level...but the plant is still photosynthesizing. Sugars and starches are being manufactured from the nutrients the searching roots are pumping up to the leaves. |
tease transplants to new location... |
When a plant is dug up and replanted...or taken from a container and put in the ground...the roots are always disturbed. To assist them to grow into soil in their new environment, the roots of a potted plant must be teased apart quite vigorously so that they can make intimate contact with the welcoming environment of the new, freshly prepared home. |
alert...rhodos hate too much water... |
For rhododendrons this means an open, friable soil with a high content of organic matter, located in a well-drained site. Rhododendrons hate standing in water: they drown. Their roots need loose, airy, humusy soil around them. |
cardinal rule: roots never go dry! |
One of the best and easiest ways to give them this open soil and the right acidity is to incorporate bark mulch. Up to 50% of the mix in the planting soil can be bark mulch...not too coarse and not dust either! Many people like to use peat moss...but much of the moss available today is so fine that if it ever dries out...it is very difficult to moisten it again. Furthermore, peat moss breaks down far more quickly than bark mulch.
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guidelines for planting... |
If your soil is black, humus-rich loam, you are fortunate indeed...and no amendment may be necessary. You can plant the rhododendron as deeply as it was in the pot.
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hybrids...shallow rooted... |
Most of the rhododendrons we grow are hybrids. Hybrids result when two or more of the plants found growing in the "wild"...the species...have been combined by cross-pollination. Most of the species that have been used to make these popular hybrids come from climates that have relatively dry winters and high summer rainfall. In the Victoria area, we have the reverse. One of the consequences of our persistent winter rainfall is the nutrients that are on the surface of the soil get leached downwards quite quickly. Rhododendrons, which are very shallow-rooted, can in fact be starved in our winter because all the goodness goes past them before they can catch their fair share. The roots can't supply the nourishment, then the plant will draw from its stored reserves...its rainy-day account...leaving less for production of flowers and foliage. |
Norm's fertilizer regime... |
The regime I follow is to feed sparingly with a chemical fertilizer (10-8-06 with all the minor elements)...five times a year. Start in November and feed every two months with the last feed on Canada Day (July 1st)...rhododendrons are not gross feeders...but they do like three meals a day...light ones in the winter, heavier ones in the spring. |
it's your choice from some 23,000... |
Choosing the right variety for the right spot is important. There are now more than 23,000 registered hybrids. This is a daunting number...but...from its very size, you can be sure that the right plant for your particular location can be found.
Colors range through the entire spectrum…except for the pure gentian blue. Even that is now a possibility with our increased understanding of genetics. |
most portable of all... |
One of the convenient characteristics of rhododendrons is that because they are shallow-rooted, they are very portable. For gardeners who would really like their plants to come with wheels so they can move things around until their concept of horticultural artistic perfection is reached, rhododendrons come quite close to being ideal. They can be moved at any time of the year. The huge majority are planted in the spring and they do well. The very best time, however, for gardeners in the Victoria area is the fall. Norm, thanks again for giving readers around the world the very basics of having rhododendrons in their garden. Looks like we are really going to have to get busy with any planned planting...and to do it NOW. |
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Geraniums...winterover |
It seems that nearly everyone loves geraniums...no matter if they are pink, white, red, or a wide range of variations. If the truth were known, all dream of wintering the plants over so they will have the same beautiful plant the following spring. The North Island editor has a few suggestions. They are in order at this time of the year...fall...when we are thinking about tidying up our "riverbanks" to get ready for winter. Three methods are suggested:
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Older, fallen, gangly, weak rhododendrons... |
Kathy Collier of the Portland Chapter is preparing us for the fall and winter months ahead. She is thinking specifically about some of our older, fallen, gangly-looking rhodos around our gardens. Unlike a lot of other plants, however, rhodos can be totally rehabilitated when they get to this condition. She indicates three major conditions...then adds...unfortunately these techniques will not work for humans! Thin and Spindly...Conditions, such as the amount of light, nutrients, and drainage, may have gradually changed over the years. Strong winds and damage from ice storms can badly damage plants...and you might not notice it...until branches begin to die-off. Heavy limbs, or trees, hitting rhodos can shatter a plant...but it may not kill it. Rot and disease, however, can creep into a wound and eventually kill plant. Typically, by the time you have discovered that a plant has stem dieback...it is already too late to save it. 'Couch potato' look...the plan may be overgrown and need a good haircut. This is not the best time to prune...but it is possible to prune out 'water spouts' or other obnoxious growth where you won't miss the blooms next year. Now...what to do: Check the soil...moles and gophers can cause dry pockets which are deadly to many plants. You may also want to check the pH, and how crumbly the soil might be...it may be time to add compost blended with some bark around the base of the plant...avoid piling up materials next to the stem. Evaluate the light...a little judicious pruning of the overhead tree branches might be just the ticket! This can be done in stages over a couple of weeks during the hot months to minimize the chance of sunburn and rapid soil dehydration. Prune out the deadwood...this can be done at any time of the year...and is a good activity to do when checking the soil. Rhododendrons and azaleas bloom on the prior year's wood...that is...wood that is alive. Dead wood does not generate blooms which is why most pruning is done after blooming. Deadhead the plant to prevent seed production...which wastes energy...and tidy up the plant. Consider pinching out single terminal growth buds to create a more bushy plant. Cut back the limb damage...to the nearest sound branch or trunk. In severe cases, this may mean cutting the plant back to the soil level and babying it for awhile. If the plant was healthy and well established, it will most likely re-sprout from the roots. It may, however, take a couple of years to recover and begin blooming again. What no one has probably ever told you... Leave a 1/8-in. stub against the trunk when making cuts close to the trunk or large stems. Not only will this heal over more quickly than a larger cut flush with the trunk...but will also minimize tissue death in the trunk. Plants cannot tolerate severe pruning at close intervals. The result could be more than just the loss of blooms. A weak plant may not heal as fast...and may be more prone to disease. Some plants grow inside limbs that can be shaded out and become weak. These stems can be removed to avoid this problem, increase the amount of air circulation, and keep stems from crossing over each other. Not all rhodos and azaleas are the same. You have probably noticed that some plants send up long, straight 'water shoots' These adventitious buds will break easily and are often liberally scattered along the stems. These stems are frequently found on azaleas and lepidote rhododendrons...those with scales...and can be cut back to any point. Elepidote rhododendrons...those without scales...however, do not develop these stems or new shoots as readily. Plants should be vigorous and in good health before pruning. Some cultivars are more sensitive to pruning as well. Some will regenerate quickly with multiple growths, while others may take years to regenerate...if ever, gradually over a few years and pruning above areas that have some small shoots already can help minimize the trauma. Root pruning may be useful when moving larger plants. Recommends pruning a year before the move to produce vigorous root branching. Kathy and Ed, thanks so much for your study and research...then sharing so we can improve the appearance of our gardens and bring health of our beloved rhodos. |
A beloved American poet friend gives some advice... |
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American Rhododendron Society
Executive Director: P.O. Box 525, Niagara Falls, NY 14304
Ph: 416-424-1942 Fax: 905-262-1999 E-Mail:
lauragrant@arsoffice.org
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