QBARS - v29n3 My Start With Rhododendrons

My Start With Rhododendrons
Terry Karas, Huntington Station, New York
Reprinted from The New York Chapter Newsletter

My experience with gardening up to 10 years ago consisted of digging a hole in the yard so that my wife could put one of her plants one day. She took me to a nursery to buy three shrubs to fill in some vacant spots. We purchased a red flowered rhododendron in bloom, a Japanese umbrella pine and an Ilex convexa. I planted the rhododendron in full sun with an over abundance of peat and drowned it every day. In a week it was dead. The other two made it and I still have them. So I figured that if I was going to spend good money on more rhododendrons I might as well go to the library and learn something about them.
The first purchases of rhododendrons after that were 'Vulcan', 'Madame de Bruin' and 'Alice', of which the former two are still doing well but 'Alice' succumbed to a winter two years later. From then on I was had. In the next nine years I had growing 50 varieties of rhododendrons and thirty varieties of azaleas. As I only have a 60 x 110 plot you can see that I have a space problem.
Some ideas that came to me through the years are as follows. We all have had the problem of not knowing whether some of our rhododendrons were flooded at root level during a heavy rainy spell. I drove a broom handle into the soil at the perimeter of the root ball to a depth of 24 inches. At the conclusion of the next heavy rain I removed the broom handle and waited 15 minutes for the water in the soil to seek its own level. I then used a dip stick to determine the water level as in an auto crankcase. I have found standing water only once and that was around the roots of a R. fortunei seedling (18") growing in heavy shade. A half hour after a prolonged ram the dip stick showed standing water six inches from the surface. The plant had wilt and was removed and the condition corrected. The reason I don't have drainage problems is because of a hardpan surface for about a foot which becomes sandy after that and then reverts back to clay at about a three foot depth. Each plant is in a $5 hole and the original soil replaced with top soil, sand, peat moss, perlite, super phosphate and a little cottonseed meal and chlordane.
The dip stick I believe would be beneficial to people growing plants in clay soils and proximity to drain pipes and leaders. The only plants that show any water problems for me are 'Rampo' and 'Purple Gem' and that is not from standing water but just an over wet root ball. Although they recover quickly after a dry spell I believe they should be planted with more sand in the mixture.
Another idea is protection of the trunk at ground level to prevent bark splitting. The material that I use on young plants is fiberglass of which we all have some left over from some project. Its benefits are that it does not rot, it prevents sudden changes in temperature, it is insect proof and it will prevent gnawing of the trunk by rabbits, etc. The fiberglass I refer to is one of the forms of insulation used between studs - fiberglass blankets which usually have paper on one side and foil on the other. The foil and paper is removed, leaving only the fiberglass. The fiberglass can be pulled apart with the fingers.
Remove a piece about eight inches by eight inches and wrap it around the trunk of your plant at the soil line to whatever height desired. This can be secured with "twistems" or clasp clothespins. The fiberglass will prevent quick temperature changes, prevent ice from forming and minimize bark splitting. Also it won't rot. I don't know of any insect that will burrow through spun glass.
(For a 5-year chapter member, Mr. Karas has a lot of plants and his favorites are: for foliage, 'Scintillation', 'K. Wada' and 'Mist Maiden'; for flower, 'Goldsworth Yellow' and 'Rochelle'; and among the smaller-leaved tribes, 'Dora Amateis', 'Scarlet Wonder' and 'Blue Diamond.')