eGarden © 2003 Ed Mues

August 27, 2003

The Lure and the Lore of the King of Shrubs

The first plant of its species was collected, classified, named, cultivated, and offered for sale in the mid-1600s. Not long afterward, the search for more and varied specimens led to expeditions that continue today, especially to the nether regions of the Himalayas and Southwestern China. Everywhere on the planet is "game". What scientists and botanists and commercial growers are seeking is new plant material of the Ericaceae, the Heath Family, in particular Rhododendrons.

The Rhododendron has been recognized as the most diverse flowering shrub with over 900 species and, more importantly, especially economically, the most ornamental flowering shrub in the modern world. Even in our computer age, there are too many cultivars to begin listing and quantifying and qualifying.

That very first specimen went by the name of Rhododendron hirsutum. It originated in the European Alps. In America today there are close to twenty-four native species, twenty being shrub-like and four being tree-like. This is still up for debate in those circles.

The Rhododendron has been ascribed the accolade "King of Shrubs" because of its great beauty, durability, and relative ease of growing. Rhododendron arboreum found in the Himalayas ascends 100 feet and contains two inch diameter flowers of blood red color in trusses of twenty flowers each. Close your eyes and for a moment imagine it. What a magnificent sight it must present.

Another, R. protistum, has leaves 10" wide and 22" long, 3" flowers with trusses holding 20 to 30 flowers.This is what propels expeditions to that region of the world. This is what, no doubt, inspired the name which translates to Rose Tree, from the Greek. One of my resources lists and describes 606 cultivated varieties of Rhododendrons. One nursery sells 180 varieties. One is a high Alpine shrublet that doesn't exceed 2 inches in height. Diversity, interest, charm and, of course, mystery.

Nearly two thousand years before the first Rhododendron of the modern world was classified, recorded etc., Xenophon, the Greek general and historian recorded after passing through Eastern Pontus, along the eastern Black Sea in ca. 400 B.C. that inhabitants were performing acts, meant to be kept private, in public places for all to see. Further investigation led to the description "honey madness", which had taken hold of the towns people. The "honey" was collected from hives that bees manufactured from local Rhododendron blossoms. Anyone ingesting this honey was in"toxic"ated by what is today known as "grayanotoxins" found in the entire Heath family.

A few hundred years later, in 67 B.C., the honey from Rhododendron flavum was so toxic an entire Roman army was overcome with "rage, madness, vomiting and loss of their senses" and the army was slaughtered by the Pontic (Greek) army, and a three year power grab was ended by what ostensibly comes down to a plant. My guess is that the same plant from the same region is the key player.

Honey bees were the agents employed. They are not political and don't discriminate. Fast forward fifteen hundred years and we learn that Native Americans, known to be keen observers and students of nature, collected and ground the seeds of the native Rhododendron to a powder and used it to kill fish. They also used the toxic leaves to make ointments and teas to treat toothache, pleurisy, stomach ailments, and a host of other symptoms. All toxins are a matter of degree, I suppose.

So, we've long known that almost all relatives in the Heath family can be toxic to people as well as livestock. Yet, after fencing off our fields and meadows, we long to have some of these outstanding ornamentals around our homes so we can admire them up close. What are we to do? We are charged with responsibilities as I see it. First, to the plant. We must provide it an acidic, well drained, reasonably fertile soil in a site that is free of harsh winter winds and strong winter sun. We must protect it from predatory damage, mostly deer in seasons where there is a lot of pressure on them to obtain food. We must assure ourselves that our animals, pets and loved ones know about the toxicity of the plant parts and are excluded from intimate contact.

Last spring I was charged with the responsibility of protecting a very lush perennial garden bed from deer feeding damage. Since the bed was not any deeper than six feet wide, I drove 8 ft. oak stakes into the ground a foot or so deep all around the garden, and wrapped the entire bed with strong woven mesh fence with approximately 2x2 inch squares. I stapled it to the stakes and kept good tension between stakes. Since the area inside is small, it discouraged deer from jumping inside the bed. You can do this in fall with individual Rhododendrons and, if the stakes are far enough out from the plants, you'll have no feeding damage.

Another tactic, if you are a true Rhododendron devotee, is to do a little research. Did you know there are Rhododendron cultivars that the deer abhor? Two new words have entered our horticultural vocabulary in recent years. They are not common, but they are important as far as deer feeding is concerned. "Indumentum" and "tomentum" are terms used to describe a thick, woolly, hairy, furry, pubescent, felt-like growth one the under side of mature leaves and even on the top side of new growth of certain Rhododendrons. They are especially attractive to aficionados who relish the attractive foliage with its underside coated with a velvety white, pale fawn, brown, or dark rusty red. These the deer avoid as completely unpalatable.

Suffice it to say that we already know Rhododendron foliage is toxic to them besides. They browse it when they are so stressed for food, it is something to fill their stomachs with. DEC wildlife agents tell me after every severe winter they find deer dead in the woods from poisoning. Their bellies are full of Rhody and Mtn. Laurel leaves. Of no nutritional value, and toxic.

These newly cultivated Rhododendrons won't be touched by even the hungriest deer. Look for Rhododendron cultivars with the names 'hellikki', mikkeli', smirnowii', and 'yakushimanum'. There are very many out there that are very pleasing to own and easy to grow.

From The Garden of Ed. Submitted for publication in The Towne Crier on August 27, 2003

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