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Rhododendron and |
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ARS Home Page R&A Home People and Events Gardens Ideas for Chapters |
Plant Tips |
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Spring culture tips |
Here are a few suggestions from the Mason Dixon Chapter to aid with the Spring care of your rhododendrons:
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A slice of bog in your garden? |
From the Rhododendron Society of Canada, Toronto Region, comes the most interesting information for Spring. This is the time of the year when some of you will be picking up bales of chunky peat moss for your rhododendron garden. Peat grows in bogs. The word "bog" brings to mind a smelly, uninviting quagmire swarming with hungry mosquitoes. But...read on and you will see that peat bogs are interesting places that don't fit the common image. Bogs are found in cool, moist regions once covered by continental glaciers, some 12,000 years ago. Canada has more bog land than any other country; those adjacent to Hudson Bay are several times larger than Lake Superior or Nova Scotia. |
Bog facts... |
Although a bog is soggy and wet, it is not odorous. A multicolored carpet of sphagnum forms the surface of the bog. This moss converts rainwater into an acid, discouraging the mosquito from breeding in the bog itself. The mosquitoes breed farther way on slightly higher wet terrain surrounding the bog. But, the acid of the bog does more... A key role in formation of the bogs is played by the sphagnum moss. The carpet of moss may be one to two meters or more thick...and be more than 400 to 500 years old. As the sphagnum on the surface grows upward upon itself, the older layers die and accumulate, forming peat. In forests, dead material is incorporated into the soil by fungi and bacteria. The sphagnum, however, releases organic acids (such as brown-colored tannic acid) which inhibit growth of bacteria and fungi. Dead moss remains intact and gradually compresses under its own weight. Thus, the surface of the living sphagnum gradually rises, resting on top of the previous now browned-off generations of dead sphagnum moss. This mass of brown peat moss is the stuff dug up and sold to you as chunky or powdered peat moss with a pH ranging from 4 to 5, really acid stuff! |
Reason for peat moss being spongy |
Under a hand lens or microscope, one can see that a network of large and small cells gives the plant a water-holding capacity of more than 16 times its weight. This characteristic allows sphagnum moss to draw up the water table as it grows upward. Without any bacteria and fungi...because of the acid...peat moss is sterile. During World War I it was used as a substitute for surgical wound dressings. Imagine the surprise of Danish peat moss diggers when they found a human body near the bottom of a bog. Scientists believe the body to be 2000 years old. The body, and even the leather belt and cap, were well preserved in the brown acidic water due to absence of oxygen and bacteria. Rhododendrons like the acidic sphagnum peat moss because this material will assist you in preparing a growing medium for rhododendrons with a range of pH between 5 to 6, as well as providing a water and nutrient-holding medium. Although sphagnum peat areas are abundant in Canada, many of these areas are inaccessible, and they need long periods of time to form...at least 400 years or more. Such time periods are several times longer than Canada's existence as a country...and such periods of time to form peat bogs equal that of our 2000-year-old Western civilization. The point is: sphagnum peat is a slowly-renewable resource. Overuse as a horticultural soil amendment can easily lead to the depletion of the accessible peat areas and drive up the price...while leaving gouged out areas in the ground. One can help by using as much composted organic materials...leaves, newspapers, cardboard boxes, and straw...as one can get, in combination with the very plentiful sulphur materials. Wise use of peat is neat! Adapted from a Pacific Rim National Park brochure and modified for consumption by rhododendron gardeners. |
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"Dirty" speech leads to garden success... |
The Eugene Chapter, Oregon, received some very basic guidelines for "dirt" and how to take advantage of this very basic ingredient from Larry Landauer, owner of Floraland Nursery, Forest Grove, Oregon, who gets down to earth at his nursery and in his talks. Listen to some of his advice for a more beautiful, healthful garden. He guarantees you'll reap rich rewards. Four purposes of dirt:
Have problems with your plants? The cause: plant is either too wet or too dry! And...all other problems are related, says Larry. He states that the soil at Floraland Nursery is "so unique" that it has its own designation in the soil categories of Oregon: "Aurora Muck". What's that? He found that it has "nothing organic" in it and holds water very, very well. It has the consistency of pudding! How to fix your "not too good soil":
Evaluate plant's health:
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Those time-release pills... |
Larry directs attention to those "little pills" you see in purchased pots or flats of new plants, emphasizing that all of them don't work the same way. He urges gardeners to carefully time the type of time release to the stage of growth that their target plant is currently experiencing. And, the different brands of time-release products work with different time-release cycles. Release cycles may be water activated or temperature activated. He emphasizes that rhododendrons "never do get completely dormant." He fertilizes in November, January, and March, and sometimes uses moisture meters to maintain correct garden levels. For container mixes: He uses 60 percent fresh fir dust, 15 percent peat moss, 15 percent sawdust, and remainder, river sand...for weight. |
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Frost damage |
Frost damage is a real concern for many, depending on the area in which you live. Frost damage causes considerable damage to: leaves, stems, buds, and flowers. Careful consideration should be given to the planting of tender varieties. This is what happens if frost damage has occurred: the leaves will become distorted, curled, and often grow only on one side of the main vein. Once leaves have been frost damaged their distortion will become less after new uninjured leaves begin to develop...if too unsightly...remove them. Frost can also cause the bark of affected stems to split longitudinally near ground level, sometimes peeling away. This usually happens in early Fall or late Spring when the plant is not fully dormant. Often these symptoms are overlooked and the damage is only noticed at a much later date. If noticed fairly recently after the injury...and before the bark has had time to dry out...the area can be wrapped with galvanized wire or a non-sticky wrapping. Ensure that the wire is removed, if the union is successful, and check the wrapping monthly. Caution: do not use duct tape. (From the North Island Chapter Newsletter) |
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Simple tips for small measures |
Have you often wondered about measurements? Especially small measures? Have a solution for you. Use your cookbook! Remembering that...
So...if instructions call for 1 tsp per gallon of water, divide 60 by 16 to get about 4 drops. Use eyedroppers to measure drops. |
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Efficient weed killer: vinegar! |
Who would have ever dreamed that this liquid called "vinegar" can be used as an efficient weed-killer. But there's more to it than the familiar table vinegar. It's 20% acetic acid. Here's what happens:
This acidifying effect can last up to a year, depending on soil type and weather. Once the soil pH is lowered, taproots will eventually starve...but might have one fast flush of growth from nutrients stored in the roots.
(Source: Ann Lovejoy, Fine Gardening, #91) |
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Notes on fertilizing... |
Allan Murray, Cowichan Chapter, has given talks and guidelines for successful fertilizing and recently wrote an informative article for the Chapter newsletter. It's excellent and now we want to share these guidelines with the world. The quality and quantity of the flowers on your rhododendrons next year depends greatly on what and when you feed them this year. Nitrogen, phosphorus, and potassium are three elements that you need to keep plant growth in proper balance: in terms of growth, flower set, and leaf color. A properly fertilized plant is hardier and can withstand more cold than one underfed. |
the right elements... |
Applied in the right amount:
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identify deficiencies... |
You can easily identify deficiencies of these elements in rhododendrons with these symptoms:
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get plant information before fertilizing |
Before you begin to fertilize, Allan points out there are several important steps to take:
This information will help you determine how much fertilizer your specific plants need. For example: water use or rainfall will determine the amount of fertilizer needed; overhead and sprinkler systems may require more fertilizer applications per year as the water will wash away some of the fertilizer; drip or restricted water systems may reduce the number of fertilizer applications per season. |
selection of chemical fertilizer |
Chemical fertilizer comprises non-organic material, it is quick acting, and is usually cheaper and more convenient than organic fertilizer. Green Valley's 10-8-6 rhododendron fertilizer comprises:
This fertilizer was developed by Tom Brown, head of the Geology Department at the University of British Columbia, and a member of the Vancouver Rhododendron Chapter. Schedule dates to apply chemical fertilizer:
Later fertilization is not recommended: soft succulent growth is the first to be damaged by a freeze; the plants need to be in a mature woody condition for when the cold weather arrives. Sprinkle 3 to 4 oz per sq. yd. at the top drip line of the rhododendrons...taking care to avoid spills on the leaves. If left on, the fertilizer will burn the leaves. |
organic fertilizer |
Allan's organic fertilizer is made of once living materials or byproducts of things once living, e.g., blood meal, bone meal, manure, and/or compost. It is slower than chemical fertilizer, but feeds longer. Organic fertilizers are ideal for rhododendrons from the standpoint of both nutrients and humus. it is made as follows (measure by volume):
To apply an organic fertilizer: with its trace elements, the fertilizer will release slowly for two to three years, but should be applied each year for maximum benefits. When to apply depends on the weather. Generally speaking:
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Keeping your rhodos happy! |
All of us are most interested in finding new ways to keep our rhodos happy...all year round. Well, Norman Todd, North Island Chapter, who has had his own nursery for about 20 years and has more than 300 species and 900 hybrids in the garden. These are some ways he has found to keep happy rhodos in your garden:
This formulation contains all 13 elements needed, and 50% of the nitrogen is offered as sulfur-coated urea, when is released over a long period. Most common reason for yellowing of rhodo leaves is: shortage of nitrogen. Solution: add fish fertilizer 5-2-3 or Miracid 30-10-10. Yellowing can also indicate a shortage of magnesium. Solution: use Epsom salts...15 milliliters to 4 liters of water. If this doesn't solve the problem, use chelated iron. Should you prefer organic fertilizer, the following mix, developed by Alan & Liz Murray, Cowichan Chapter, is recommended:
Note: Norman recommends, if changing to organic feeding, do it over time, overlap applications, as this mixture takes time to break down and release its nutrients. Norman strives to make his rhodos happy and encourages you to do the same. Simple enough. |
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Use for old shower curtains |
Here's a significant use: old shower curtains make fine garden tarps, cover piles of compost or leaves, and for gathering weeds. Time to start planning now. Just think of the garage sales you can go to and buy the curtains for a song! |
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Removal of caterpillars... |
The Nanaimo Chapter's newsletter had an interesting cartoon of a bird pulling a caterpillar out of the ground...and offered this advice. You can wait for the birds or try the following:
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Healthy rhododendrons need healthy roots. |
Have you wondered why your rhodos are not as healthy as you expected them to be? You may not have considered four extremely important factors to have success. Eileen Hoffman of the Nanaimo Chapter, Canada, replied to Richard White who asked a similar question...and she gave him the following guidelines. First, that clump you bury in the ground and never see again...that clump is actually a mirror reflection of your plant. Simple enough. Growing healthy roots...grows healthy rhododendrons. Second: consider the following: Location: rhododendrons roots are surface feeders, developing a shallow root system. Because rhododendron roots obtain much of their oxygen and water near ground level, do not plant too deep, providing them with adequate water. This is achieved by digging a shallow hole and backfill hole with amended soil (soil mixed with mulch). Place roots half way in hole, lightly cover the top of roots with mulch. One nice point to having a shallow root system is they do transplant fairly easy. Water/Drainage: rhododendrons roots love water. They can sit in it when the temperatures are cool, but when it is hot and humid, they can develop root rot. Some tips:
Not recommended: using fallen leaves because they can contain disease, but they do make a nice top covering in winter months. Spacing: When planting consider spacing and these factors. A quick and general rule is:
Fertilizing: Is it lunchtime yet? Yes! Rhododendrons roots get hungry, too! Recommend feeding rhododendron roots as early as March, then a small dose every 4 to 6 weeks until mid-July. Fertilizing after July can initiate Fall new growth that is susceptible to early frost. You can purchase rhododendron/azalea food at your local garden supply store. |
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Something to share...dreams...what are they? |
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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
©1998-2016, ARS, All rights reserved.