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A Few Tips on Winterizing your Rhododendrons

I thought that I might also share some tips with you as to how best to prepare your plants for cold weather. These tips are mostly from The American Rhododendron Society(http://rhododendron.org/) who are a great source of information for rhododendron growers.IMG_2060

  • Hydration is important for the winter. If you have the ability for a good soaking in late fall and covering with mulch that will hold the moisture and insulate the ground around the root system as long as possible, your plants can use this moisture intake to help their systems during the freezing winter months.
  • Protection from drying winds. Planting I areas that are sheltered from winds are recommended. If you have plants that may have wind exposure, creating a wind break or wrapping in burlap can help protect them.
  • If you plants are in containers, move them to areas that are close to the house and/or onto the ground where they can use the warmth that is radiated by the heat of the house and ground.
  • A customer from Connecticut suggested spraying with a 5:1 dilution of Wilt-Pruf in November on a dry day above freezing. This will help in preventing wind damage.  He reminded me how difficult it can be to spread a trap or burlap on mature plants that can be 15 feet tall!  Thank you Bruce!  Here is a link to Wilt-Pruf on amazon.
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Phytophthora (Root Rot) in Rhododendrons

I have received many questions about rhododendrons that could be considered “tolerant” to Phytophthora from people who have lost plants during the long, warm wet summer. Digging into the archives, I found this article that was published in 1975 by the American Rhododendron Society by research done at The Ohio State University.  Though this article was published over 40 years about, many of the hybrids and the species rhododendrons that were available at the time are still available today.   I do not carry any on the very short list of resistant hybrids, however I do offer many that are on the second short list  of “moderately resistant” and “more tolerant”.  These are the plants that we currently offer that are on this list:

English Roseum( Purple, Hardy to -10, 7 Feet) http://oregonrhododendron.com/product/english-roseumaka-roseum-pink/

Mrs. C B Van Nes (Dark Pink, Hardy to 0, 5 Feet) Only limited number available in one gallons – please e-mail.

Rocket (Dark Pink, Hardy to 0, 5 feet) http://oregonrhododendron.com/product/rocket/

Roseum Elegans ( Pink, Hardy -10, 7 Feet) http://oregonrhododendron.com/product/roseum-elegans/

The Honourable Jean Marie de Montague (Red, Hardy to -10, 5 Feet) http://oregonrhododendron.com/product/the-honourable-jean-marie-de-montague/

Vulcan (Red, Hardy to -10, 5 Feet) http://oregonrhododendron.com/product/vulcan/

Vulcan’s Flame (Red, Hardy to -10, 5 Feet) http://oregonrhododendron.com/product/vulcans-flame/

I do not carry any of the species plants that are tolerant or moderately tolerant.  Due to the age of this article, there may have been new hybrids that have been introduced or further research done to determine tolerance.  Any new information I receive, I will post to this blog.  Thank you!  Jim

http://scholar.lib.vt.edu/ejournals/JARS/v29n1/v29n1-hoitink.htm