JARS v38n3 - Hybridizing Deciduous Azaleas

Hybridizing Deciduous Azaleas
David Reeder, Clarksville, MD

Reprinted from New York Chapter newsletter

Editor's Note: David Reeder gardens in Clarksville, Maryland. He originally presented this program to New York Chapter members on February 18, 1982. His talk was accompanied by excellent slides of his representative seedling deciduous azaleas in a variety of dazzling color combinations.

About fifteen years ago I acquired three Mollis azaleas from an unlikely source - the Montgomery Ward Garden Catalogue. Only one survived, but it pleased me so much that I propagated in peat moss under a brick. Two years later I had a new plant. (The old one had died), but alas, technology triumphed when our young son mowed it down with our new Montgomery Ward Mark Six riding mower. So much for that.
Although we lived in the country on one and a half acres, as a gardener I was experiencing various frustrations. Half of our yard was devoted to an interesting menagerie of pets which had escalated from mallard ducks, rabbits, chickens, and pony, to a lonesome horse who needed a braying donkey for companionship. The rest of the yard was so windy that evergreen azaleas had their leaves blasted away, their stems split open and their remains eaten to the ground by wild rabbits.
So I built a small greenhouse, and with cheap energy available with the flip of a switch, I raised all kinds of greenhouse plants during the winter. One year from a single packet of gloxinia seed, I grew so many gloxinias that we resorted to giving them away to all of our friends. We ran out of friends before we ran out of gloxinias.
In 1968 I saw a small advertisement in a garden magazine for hybrid deciduous azalea seed; Knap Hill Nursery Ltd., Barrs Lane, Knap-hill, Working, Surrey, England. I ordered four packets for about Ten Dollars, which arrived none too promptly at the end of March. I followed their instructions, planting them in peat moss, and, to my amazement, found that about two thousand azalea seedlings had germinated within three weeks! The first step was obviously easy, but I found no help in the instructions for what happened next. Thanks to scorching sun, torrential rain, two cats who used my beds as conveniently placed, spaciously proportioned litter boxes, and a dog who found azalea beds to be a cool place to sleep, I lost all but fifty plants, and even those were to be decimated later by rabbits.
Not being one to give up easily and remembering those two thousand seedlings which I really had for a short while, I laid plans for next year. I had wasted a lot of peat pots in the past and decided that the Styrofoam hot cup was the cheapest reusable container on the market; they were also discarded in profusion after our church's annual ham and oyster supper. I bought and scrounged about two thousand of them. Outdoors, scattered beneath our slowly growing pine tree windbreak, I prepared twelve six feet square beds, bounded by logs. I pounded roofing nails into these logs, from which I planned to string a binder's twine net, to keep the critters out.
Spring of 1971 was a partial success. Seedling which sprang up as before, were transplanted into hot cups and by April were about an inch high. In May they were laboriously planted into the prepared beds, and although my Achilles tendons and back gave me fits, I survived somewhat better than did most of my seedlings. They were pitifully small and I watched thundershowers beat them into and out of the ground. Weeds flourished exuberantly in relentless succession: chickweed, oxalis, purslane, goosegrass. I became my own worst enemy when I weeded, because I invariably pulled up azaleas at the same time. But, next spring I was impressed by the tenaciousness of these plants. Many survived, even when heaved out of the ground - hanging in there by the tips of their roots.
If only my plants could be larger when I first set them out. I wrote a letter with my next Knap Hill order imploring them to send the seed earlier. They did, without comment, in Late December. I started them off at once in the basement under a bank of fluorescent lights. I had some vigorous three inch seedlings by spring and lots of them. But I had to face up to an old problem. Among my almost blooming sized plants there was an awful amount of indiscriminant pruning by rabbits. All winter long there had been no damage, but as spring burst forth with green grass and clover, those rabbits suddenly developed an insatiable craving for azaleas. They sampled them all and some plants they nibbled down to the nubbins. Nevertheless, I was absolutely astonished by the variety of colors displayed by my ragtag little army of blooming azaleas: bi-colors and tricolors in red, rose, pink, yellow, cream and white, most showing the characteristic gold flare on their upper petal. I would have to protect these gorgeous, though somewhat deformed plants at all costs.
1973 was a good year, but best of all I retired from my Civil Service job after thirty-two long years. I began to thrash about wondering how I could justify this hobby and continue sending my kids to college. I would sell plants cheaply of course, just enough to pay for my seed, peat moss, fertilizer, mulch, light and heating bills, and the new chicken-wire fencing which I had just placed around my outdoor beds. Being an old son of a missionary, and cursed with an overactive conscience, I made inquiries about whether I had to charge a sales tax on plants that I sold. I got a fast answer. Indeed you must, and you must also have a license from the State of Maryland, Comptroller of the Treasury, Retail Sales and Tax Use Division. I became the owner of a small business. License Number 14 05280 R, desperately in need of professional help in figuring out my income tax. My first year of sales yielded a net profit of $18.00, out of which H.&R. Block received $55.00.
On a trip to Longwood Gardens I picked up a booklet entitled "Handbook On Rhododendrons And Their Relatives" which contained an article by Henry T. Skinner entitled "America's Native Azaleas". It gave a fascinating history of their contribution to the genetic heritage of the Knap Hill and Exbury hybrids. On the back cover of this booklet was a little box which said, "American Rhododendron Society Invites Membership". I enrolled as soon as I got home.
My blooming plants were starting to stop traffic. Although I did not advertize, I did hang two signs on a large oak tree, "Azaleas for Sale in May, $5.00" I only sold blooming plants, but it was obvious to most of my customers that somebody got the very best plants first. He made a sneaky pre-breakfast check of the latest blooms and sidetracked any plant that showed new colors or unique characteristics. Those plants were removed, mulched, and permanently planted in his own yard before you could say "Cuppa Coffee". Please don't get the idea that I was a spoil sport. I only took about one out of thirty plants and I was perfectly willing to part with duplicates. Most visitors concede that, after waiting three or four years for a bloom, the grower should have first digs. Actually it took a lot of willpower not to establish all of my blooming plants in every corner of our yard. One man looked at me with a discerning eye and said, "You don't really like to sell any of these azaleas, do you?" as he drove off with nineteen plants in his pickup truck; included were several prizewinners that I had missed. Once a woman who had enthusiastically toured the yard while I was busy with another client, consulted her notes and said briskly, "I'll take number 17, 43, 127, and 28," referring to my numbered specimen plants. I turned pale diplomat and steered her to my fenced beds, where she picked four smaller plants with equal enthusiasm.
I will now describe in excruciating detail my latest procedure. I collect seed from October to November and classify my seed by color, just to be sure that I get an even mix. I collect seed only from my specimen plants of which I have 273 at this time. In early December I plant the seeds in peat moss filled flats, which are simply gallon plastic milk jug bottoms, about 2 inches high, with no drain holes. Under fluorescent light fixtures, the seed germinate in about three weeks. By early January, about a thousand seedlings have been transplanted into hot-cups with drain holes, and two-thirds filled with peat moss. These are nested by fours in those ubiquitous milk jug bottoms, which now serve as saucers, and are placed on a plastic canopied ping-pong table,* illuminated continuously by fluorescent light. Although the basement temperature hovers around 52 degrees during the winter, the fluorescent lights keep the temperature under the canopy between 55 and 60 degrees. Plants are watered about every five days and fertilized periodically with "Miracid" or fish emulsion. The fish emulsion seems to generate manure flies - a holdover from horse and donkey days. These are controlled with a light treatment of "House and Garden" aerosol spray and the canopy helps to keep the spray over the "Garden" instead of all over the house.
By April my plants are from three to ten inches high and some have even been pruned to keep them from becoming too floppy. I anxiously wait for what I hope is the last frost.
May is pandemonium. I move seedlings to outdoor seedling beds, move yearlings from seedling beds to digging beds, dig blooming plants for customers from digging beds and end up with, guess what? A hole in the ground. A dirt deficit. My small business is gradually sinking me and my yard into a deep depression.
Well, I have this very dirty station wagon. I also have the good fortune to own nine acres of land fifteen miles away near Sykesville. It is a beautiful spot surrounded on three sides by undeveloped State Park. Two neighbors out front, in landscaping their yards, pushed large piles of their finest topsoil onto our property line and are only too happy to see me carry it away in five gallon plastic pots. They even have an enterprising young lad who hauls these pots up the hill for ten cents a pot; correction twenty-five cents a pot (a deductible business expense), and by spring I will have as many as 275 pots at the ready, stashed mostly under our spirea hedge.
I have not been very successful in my few efforts to hand pollinate; anyway the bees seem to do it better. A large blossom seems to need a large pollinator, and I have watched enormous bumble bees coming from God knows where, to do the job.
I have not lost many specimen plants, but I do admit to spending a lot of some summers at the end of a 250 foot hose.
I do not plant Mollis seed now. They suffer from bud blast in our colder winters. They tend to bloom themselves to death in good years and no amount of care will bring them back to their former glory.
I will mention two problems which have plagued us for many years. My seedlings would start losing their lower leaves and some would die just as I was on the point of moving them outdoors. The other problem was the blue-green discoloration of our bathroom fixtures and the corrosion of our copper pipes by acidic well water. At last (my wife agrees), at last I have installed a water conditioner which I believe will remedy both problems. Copper salts are bad for plants and people.
A Mrs. Winner from Boring, Oregon informed me that all of my 1980 seed contribution came up, or down, in a heap of grey mold. I did not consider this news boring at all! I have never had any trouble with mold, fungus or damp-off. I sent her seed directly in 1981; she reports a bumper crop, and she is on the way to being a winner after all.
A four year old plant is pretty safe from rabbits, but several winters ago I found to my dismay that deer had browsed the buds off the tops of many of my largest plants. The cruel winters of '77 and '78 did kill some flower buds, but I don't think that the cold has killed any of my specimen plants. However it is obvious that a lot of cruel natural selection takes place among my seedlings before they reach blooming size. About half of my seedlings never make it through the first three years and now it does seem to me that hot summers, rather than cold winters are what punish my plants the most.
I am partial to red, but red has been my most difficult color. They bloom late, and in a tough year they refuse to make seed. Lavender is not my favorite color, but when a lavender blossom came from nowhere three years ago, I got all excited about it, because in my inventory it is so rare.
My earliest bloomers are the Mollis. They don't smell too good. "Hey there's been a skunk walking around here," says a customer as he digs his own. Not skunky, but foxy as an Englishman expressed in his own idiom. Some of my Knap Hill hybrids are exquisitely scented.
Rhododendron shows tend to be a little early for me. We are 20 miles north of Washington D.C.; our country temperatures are lower by 10 degrees, and even in my yard, my downhill blossoms are a good 10 days behind my uphill ones. If you divide the blooming season into early, early-mid, mid, mid-late and late seasons, my collection shows a curious pause after the early-mid. I become discouraged but then some truly spectacular hybrids bloom throughout the mid to late season and it is these blossoms that I have never been able to take to a flower show. This may explain my enthusiasm in showing slides to captive audiences.
One of the most frequent questions I hear is "When and how should I prune the plant"? Well, most young plants are gangling and do look like they need to be pruned. Given their propensity to branch, with better than half sunshine, they will all become well shaped plants with lots of buds. On the other hand, in the shade they will hardly bloom at all. I only prune out dead wood. I am also asked if I can predict the color of a blossom by the color of its buds or leaves. I cannot. About the only hazardous prediction I'll make is that a plant with reddish-bronze leaves will likely produce a late blooming rich orangey blossom someday. I have also learned not to judge a plant by its first bloom. A small blossom may later become many large blossoms. Sometimes I have sidetracked for myself a plant with a single blossom of surpassing beauty which has not been given a second look by others.
I have tried to raise all of the hardier American native species and hope to naturalize them out at Sykesville. That is our "arboretum" which so far can only qualify as the poison ivy capitol of the world.
I have a little book in which I record a short description of each specimen plant. I enjoy naming certain ones informally after family members; they pick their own favorites.
I wonder now if there should be a limit to the number of plants that I collect. My method of growing deciduous azaleas has become a fairly easy ritual now which I intend to carry out as long as I am able. But shouldn't I try now to duplicate the one's I have? This hobby has been one seemingly endless series of surprises and I still can hardly wait to check out the new plants that will open next spring.

* One ping-pong table will accommodate 720 plants.