QBARS - v6n3 My Quarter of a Century with Rhododendrons

My Quarter of a Century with Rhododendrons
Charles Herbert, Phoenixville, Pennsylvania

This article is written for the gardeners who would like to have some of the world's most gorgeous plants, not only in flower but to add color to the garden the year round, with a minimum care. To these people let us grow rhododendrons.
This garden was planned as a rock garden and rocks weighing one half ton were placed on a slope facing the north. The plants were put in place and I was just going to sit back and enjoy the fruits of my labor.
It took me some time to find out that a rock garden and the growing of perennial plants was too expensive and took up more time to care for them than I could give. I had a lot to learn. The first winter took a heavy toll of the plants. In the first planting were six small 'Hinodegeri' azaleas, some Mountain Laurel and R. nudiflorum , and these plants that I thought would die continued to flourish and after twenty-five years are still in the garden-while all other plants are only a memory.
As these rhododendrons did so well I decided that from then on the main planting would be rhododendrons. The first hybrids were an unnamed red and an orchid. These two plants are now about twelve feet high and nearly as broad. The next plants were the native species R. calendulaceum , vaseyi , viscosum , arborescens , catawbiense carolinianum , maximum and minus . About six plants of each kind were grouped together according to their species. For shade the native Dogwood and Redbud, and for evergreen trees Holly, Hemlock and White Pine. Kalima augustafolia and Leucothoe are used for ground cover. One or more of the following hybrids are used in this planting.

The only one that does poorly is 'Britannia '. Winter weather kills some of the branches.
If you decide to grow rhododendrons, look around and if your neighbor has them and they grow good then you can too. It is best to have your soil tested to find out if it is acid, and if your soil is not all clay, has good drainage, a liberal amount of humus, a little shade and sheltered from strong winds the rhododendron will do well if these requirements are met. Never plant deeper than it was growing in the nursery. If you do the plant must grow anew set of roots before it will make any kind of growth. Buy your plants from a nursery near you -there are several reasons for this.

1.  The soil will be almost like your own.
2.  It has been acclimated to the winters in your vicinity.
3.  It will be freshly dug and not dried out.

A plant grown in sand takes too long to get established and will dry out. I have seen plants die and when you pull them up the roots are just as they were planted. Fertilizer is another stumbling block. It is like medicine, you don't take it if you do not need it. For planting, a handful of superphosphate placed in the bottom of the hole and a handful of cotton seed meal mixed with the soil will be all the plant needs for several years. I would never use an inorganic fertilizer in an established planting because the tendency is to over do the job. Cotton seed meal can be used and an over dose will do no harm. Herein the east we have a fish fertilizer that is also good. If your plants are good and green and bloom fairly well don't use fertilizer. This is especially true of the native species. If you want to see Mountain Laurel turn up its toes just use some inorganic fertilizer on it. If you must use the hose as I do, sprinkle a small amount of sulphur around the plant in the spring and fall. This will keep your soil acid.
If your azalea's turn yellow one ounce of iron sulphate in two gallon of water sprinkled over the plant will do the trick. Water your plants well before freezing weather sets in, put on a thick layer of oak leaves or peat moss and that is all there is to it.
I would like to make a report on the Glen Dale azaleas. Having tried about a hundred varieties I find that the young plants are subject to bark rupture in some of the varieties and others die roots and all much like young plants of indicum or R. mucronatum . Plants four years old seem to stand our winters but I doubt if they will grow good in the Pacific Northwest. However, they are worth a try and are good bloomers. For myself, I would rather grow Mr. Gables azaleas as they are evergreen the year round and very hardy. He has developed some wonderful plants. I also have a nice collection of Ghent hybrid azaleas which grow and flower well. R. molle and the hybrid do not grow well as they seem to die back. This location is fairly well suited for the growing of rhododendrons. The temperature does drop to 10° but has never hit zero but once that I can remember. The trouble here is to find the plants you want, the ones I have were collected from almost everywhere. I am still trying to find some blooming size plants of R. fortunei , discolor , ciliatum and yunnanense but without results, and I am looking forward to the day when some of the new hybrids will be available to the east coast section.
The first rhododendron to bloom here is R. mucronulatum , blooming about the middle of March, followed by R. schlippenbachii , and by the second week in April R. carolinianum is blooming. This year all the hybrids are about ten days ahead of the usual flowering date. Some years ago some seed of R. carolinianum came up and out of these plants one is unusual. The flower is about the color of the Kurume azalea 'Daybreak', but more trumpet shaped than R. carolinianum and have red dots on the upper petal. The leaves and growth also are different and it is most striking in appearance among the dark green leaves. I also have some young plants of a cross between azalea 'Hindodegiri' and 'Amoena' - these will bloom next year.
I planted this seed on the moss that grows on the big sand stone rocks outside. The hardest job is to pry the young plants loose from the rock as the roots grow down into the sand stone. You lose some plants the first year, but the ones that pull through the winter are sure to be hardy. I have let this planting develop without much thought as to thinning or shape because I like a natural setting rather than one too formal. It is a haven for birds and a weed cannot find room to grow. When I buy a plant it is one that nobody else wants and these can be had at a much lower price than a specimen plant and it will answer the same purpose.
I propagate all of my own plants, the azaleas by cuttings and layering and the rhododendrons by layering. I find layering will give you all the additional ones you need and most of them root in two or three months. I bend a branch down and take a knife and remove a section of the bark about two inches long, weight it down with a rock and pack wet moss around it.
In conclusion, any one will find that growing rhododendrons is a fascinating hobby and well worth the effort it takes to make a success out of your planting. I know it has been with me and there are many new adventures awaiting around the corner.