Reflections on Muck and Mysticism
Reprinted with permission from American Horticulturist, 1984
Some 10 or 12 years ago at an annual meeting of the American Horticultural Society in New Orleans, I had a chance meeting with L.C. Chadwick, who had long served as head of the Department of Horticulture at the Ohio State University. There was a tour of plantation gardens that day and, having lingered longer than I should have over a dozen properly iced oysters at the Sazerac Bar, I was a bit tardy getting on the bus at the Fairmont-Roosevelt Hotel. Only one seat was left and, without noticing my new traveling companion, I sat down, out of breath but quite happy with the world, as anyone is who has just partaken of that number of God's finest bivalves.
I should have recognized my companion at once, for the evening before he had been awarded the Liberty Hyde Bailey Medal, the highest honor conferred by the American Horticultural Society. We introduced ourselves and had a delightful conversation. Professor Chadwick had been an institution within an institution at OSU, a Mr. Chips of horticulture revered by two generations of students. I came to understand why. He was in an expansive mood that day, and we discussed everything from house plants to well-known gardens to his particular specialty, the genus Taxus. But mostly the talk was reflective, on changes that had taken place in gardening over the years. His prime interest was, quite naturally, in horticulture as a science, as opposed to an art.
Professor Chadwick was proud of these changes, some of which he had helped to bring about, but he was quick to admit that a great deal still had to be learned about plants and gardening. So much horticulture is plain supposition, he remarked. One of his thoughts has stayed with me to this day. It was, essentially: "All my life I have heard and read that if you remove the spent flowers of a lilac or some other shrub, there will be better bloom the next year. I think this is true, but in all of the literature issued by the various universities and botanic gardens, you will not find an instance of a controlled study where someone has actually proved it." In my own years as an editor I have learned to be cautious, too.
A good friend of mine, photographer-author Pamela Harper, reads garden books and articles more carefully than I do and becomes amused, annoyed or exasperated (depending on the offense) at conflicting claims about gardening techniques, cultural recommendations or even plant descriptions. She summed it up succinctly for me once when we became involved in a discussion about one of the more obscure points of "organic" gardening: "Gardening is muck and mysticism."
Divide and Conquer
The first 20 years that I gardened I never divided a clump of monkshood (Aconitum napellus), a lovely blue-flowered perennial with glossy leaves divided like those of the common buttercup, to which it has a botanical family tie (Ranunculaceae) despite its helmet-shaped flowers. Somewhere along the path of my horticultural education I had read in several books that monkshood could not be divided, and my friends stoutly confirmed this, though none had ever tried to do it.
Eventually, a fungal disorder laid to rest our nice little thicket of monkshood, and we went without for a few years. Then a kindly soul down the road called one late summer day and offered her solitary large clump; she had young children and feared they might sample the leaves or roots, which are deadly poisonous. You see, another species, wolfsbane (A. vulparia), was used to poison the bait for wolves in Europe during the Middle Ages, and its roots were fed to criminals, knaves, wives or husbands, depending on the occasion. But, in general, wolfsbane was not regarded as a poison for the upper classes, though a competitor or two of the influential Borgia family - presumably high class - may have been done in this way. In any case, Aconitum has made its way into lore. Warlocks love it.
Mary Ann, my much better half, ventured to our friend's garden and carefully dug the clump, treating it as a shrub and getting a good amount of soil around the roots, for I had stressed to her the difficulty of transplanting monkshood. Upon her return home, she dropped the clump while unloading it from the car, and it shattered into a hundred little pieces, each with a bulbous root attached. Undaunted by my dire warnings about the uselessness of this effort, Mary Ann planted and cut back the foliage of each one, and they all happened to live. We have divided monkshood happily ever since. Indeed, several species of it.
How does such a story begin, about a plant being hard to divide? True, some perennials do not convalesce well after division or do not divide very easily. (I once spent half a morning with a pickax, getting a dozen divisions from a clump of Miscanthus grass.) In the case of monkshood, I suspect the story started this way: Garden Writer A wrote that it was a shame to divide an established clump of monkshood, because it took awhile for it to assume a stately grace. A few years later Garden Writer B came along and, finding Garden Writer A's prose turgid, said in the interest of brevity, "You should not divide monkshood," a few years later still, Garden Writer C, a careless copier, came along and said, "You can't divide monkshood." Alas, the ring of authority that comes with a simple, quick statement! Editors - and readers - love it.
Now let us alter the story a bit. If the clump of monkshood had been given to Mary Ann for division in early July - just as the hottest and driest part of summer descended upon us - the result might have been quite different, especially if we had been lax about watering and mulching. We once, in fact, lost a few divisions this way, because our New England summers are seldom as cool as they are pictured to be, even by New Englanders. If we lived in North Carolina, the July division would likely have meant death for the plants.
Why Plants Fail
One of the commonest causes of premature death for rhododendrons, azaleas and their kin is too deep planting, a sin committed by new or neophyte gardeners, especially if they live in cold climates where there is a misplaced urge to "get the roots down" so they won't be harmed by winter. Such death is not necessarily sudden, which is unfortunate because it would put an end to the practice, the gardener quickly perceiving cause and effect.
Ericaceous plants are more shallowly rooted than most, the roots being prone to desiccation if there is not an ample supply of organic matter in the soil. The organic matter also provides good soil aeration, which among other things helps roots spread properly. In addition, on top of the soil, a pine bark or other porous organic mulch, placed two or three inches from the stems to discourage rot, keeps the soil moist and loose. Should, instead, several inches of soil be added on top, as by too deep planting, the roots virtually suffocate. With rhododendrons, not to mention a lot of other plants, it can be literally a matter of life and death to study the soil line of the plant you are moving.
Incidentally, in my own experience peat moss, which cakes when dry and then prevents rainwater from passing through to the roots, is one of the worst mulches, though the commonest. Also, in the second year as mulch it can be a remarkable seed bed for all sorts of surrounding weeds. The appropriate use for peat moss is really as soil conditioner when preparing a border for planting. Some students of woody plants, it should be mentioned, are even beginning to question peat moss' utility in new planting holes for trees.
The corollary point, of course, is that we gardeners are very apt to promulgate horticultural laws based on a single instance. How often have you heard, "Astilbes just won't grow in my garden"? Or, "Shasta daisies aren't hardy for me"? In the case of the astilbe, one wonders if the sole attempt was made in a sunny, parched spot of the garden - hardly the ideal place for these woodland plants from the Orient that require a moisture-retentive soil in summer. As for the Shasta daisies, poor drainage in winter might have caused their demise, and the plants could have prospered nicely in another, more elevated, location in the same garden.
However, there are many times when we don't really know why a plant has died, and if it happens not to come up in spring, the almost automatic assumption is that it was not winter hardy. Yes, sometimes cold is the prime factor. But, apart from improperly drained soil in winter (which is perhaps the most frequent cause of death for either herbaceous or woody plants), fungal or insect problems, drought, too-late planting, rodents or some particular cultural condition all could have weakened the plant in the previous growing season, and winter merely provided the coup de grace.
One spring day when I was lamenting the over-winter loss of an unusually attractive anemone, a fellow gardening zealot consoled me by saying, "Fred, you can't really say you have failed with a plant until you have killed it three times." Later in the year I reminded him of his sagacious words. He paused for a few seconds, then remarked, "l think I should have said 'five times'!" Of course, if you are trying to grow a banana in New Jersey and it doesn't make it through the winter, there is a time for automatic assumptions.
Telling It Like It Is
By the same token, one winter's success does not spell hardiness. Nor two. Nor three. One of my good friends, Erica, hates to have me visit her in gardening season, because she considers me a harbinger of doom. I am welcome for tea, or dinner, or even travelogues on long winter evenings, but not on a golden summer afternoon. You see, Erica is a fairly new gardener and is still in the flush of great enthusiasm, some of which I hope she will always keep. She tries everything, including ornamental plantains and hawkweeds.
Several years ago after a visit to Scotland and to gardens in England, Erica decided to plant an extensive number of heaths and heathers. Two mild winters have intervened, and these plants, laden with a thick cover of evergreen boughs in the cool months (when many of the heaths are most ornamental), seem to be in thriving condition. The longer-term performance record for heaths and heathers in non-coastal parts of America is not very auspicious, though, and I have on occasion pointed this out to Erica. Next summer when the heathers are in full bloom, she plans to have a garden party and not invite me. I will come another time to admire her hawkweeds.
Telling it like it is does not always endear one to gardeners, who live more by dreams and catalogue descriptions than normal people do. Gardeners want to believe, and that is fine - even beautiful - unless it pushes reality too far off into a dark corner, to be tripped over when it is time to put on the light. Every few years, for example, some gardening magazine in the country, with new editor and new writer, carries a piece on the Himalayan blue poppy, Meconopsis betonicifolia. This is a hauntingly beautiful flower but is not a very good garden plant in the United States, except in a few areas with cool summers, and then uncommonly.
The author of the article may have seen the blue poppy in a garden in England, where it performs tolerably well, or even in Alberta (which also has cool summers). Perhaps he may even have grown it for a year or two on the coast of Maine or in the Pacific Northwest before it croaked. The article is apt to end on a plaintive and familiar note: "This fine plant should be more widely available." It once was. In fact, one of America's large perennial nurseries promoted it with pretty catalogue pictures for years before the outcry about the blue poppy's short life span made the firm realize it was engaging in horticultural genocide.
For many people the joy is in the growing, not in the end result of a garden. Some enjoy a challenge - taming the untamable plant, taking pride in raising difficult sorts to fine specimen stage. They regard "easy" plants as a bit vulgar, the sort grown by a neighbor with whom one doesn't get along. There is usually no harm in this, provided the grower doesn't kill too many lady's-slippers, trailing arbutus and shortia in the process. These are not really garden plants.
True, the vast number of endangered plant species in this country are endangered because of habitat destruction. But some responsibility must be borne by the horticultural community, since the above natives - and quite a few others - are usually dug from the wild, either by the home gardener or by wildflower dealers who then sell directly to the public or to nurseries. Fortunately, there has been an upswing in nurseries that actually propagate their own wildflowers, partly as a result of efforts by the University of North Carolina Botanical Garden and New England Wildflower Society in recent years. Many of them are easy to grow, but if a wildflower is difficult in cultivation, it may help keep the species going in the wild if we ask ourselves why we really want to grow it. Ego may play a larger part than we care to admit.
"Difficult" plants fail for a variety of reasons. For example, they may be fuss-budgets about location, there may be soil mycorrhizae associations, or their soil pH requirements may be exacting. I recall a story told me some time ago by a conservation-minded nurseryman, Andre Viette, who feels that the best way to conserve a plant is to grow it. He obtained Shortia galacifolia, a delightful and increasingly rare-in-the-wild southern wildflower sometimes called Oconee-bells. The plants, which he obtained from North Carolina, arrived in soil with a quite low pH, 4.2 to 4.7. They had to be potted on, and to increase the acidity of the moderately acid soil he customarily used, Mr. Viette added a large amount of leaf mold, mostly red oak. Don't many garden books report that oak leaf mold has an acidic reaction? The shortias languished and, on a hunch, he took a pH test and discovered that the new medium was close to neutral. The pH was adjusted downward, and the shortias began to thrive again, along with partridgeberry (Mitchella repens), coltsfoot (Galax urceolata) and wintergreen (Gaultherķa procumbens) - other distinctly acid-loving plants potted in the same mix. As an addendum, Mr. Viette pointed out that he had tested peat, too. Canadian peat was usually in the 5 to 6 range (German peat, usually lower), so the addition of this common material would not have solved the problem.
Luckily, not many of our garden plants are as demanding about soil pH as shortia, or else we would be driving our land-grant universities wild with requests for pH tests of garden soil. (Many perform this function for a nominal fee.) In general, garden plants are tolerant of a fairly wide range of soil pH levels, although there are optimums known for certain ones, especially vegetables. In high-rainfall areas soils are as a rule distinctly acidic, and the majority of plants perform satisfactorily with small or no additions of dolomitic limestone. The matter of soil pH is usually overemphasized, unless one happens to live on a bog or on top of a lime pit. I do know from quite personal experience that generous use of limestone on moderately acid soil can do more harm than good to a lot of herbaceous perennials, especially the shade-tolerant sorts such as Hosta, Epimedium and Astilbe, as well as summer phlox (P. paniculata) and Japanese iris (I. kaempferi). (The wet-soil requirement for this iris is an old wives' tale.) Dianthus, Gypsophila and Scabiosa are among the few that lime distinctly helps if soil acidity is low.
For years there was an unchallenged assumption that the optimum pH range for mineral soils was 6.5 to 6.8. This may be true for many of the traditional sun lovers, including vegetables, but the shade plants or woodlanders so common in today's gardens are usually from parts of the world with substantial rainfall and benefit from a lower pH. But what about the popular soilless mixes? Some recent experiments by Professor John C. Peterson of the Ohio State University show that 5.2 to 5.5 on the pH scale is best for such a medium. He observed that the availability of phosphorus, an element important for root growth and flowering, increased more than 10 times as the pH was lowered from 6.5 to 5.2. For his studies, Professor Peterson used a commercial mix containing sphagnum peat, perlite, vermiculite, granite sand and composted pine bark, adding major nutrients and trace elements.
But we shouldn't be too quick to take our bags of limestone to the dump, particularly if there are Japanese beetles around. At the Ohio Agricultural Research and Development Center in Wooster, some recent experiments have shown that beetle larvae decrease in number after ground limestone is spread on a lawn. In one test on a lawn whose soil had a very low pH, 100 pounds of dolomitic limestone were applied to 1,000 square feet of land. As a result, there was little grub damage, whereas, a surrounding area that was untreated was badly infested. The report also mentioned that if a lawn needs dethatching, this aeration procedure should be done before lime is applied, lest the lime "barrier" be broken. Since we had been greatly bothered by Japanese beetles in recent years, we decided to lime the lawn last autumn. (The most recent application had been five years earlier.) The happy result - probably not a coincidence - was a sharp decline in beetles this year.
The nadir of muck and mysticism was reached in our garden several years ago, and it had to do with Japanese beetles. One of the gardening magazines carried a piece on beetle control, which sounded very promising to Mary Ann. The author said that the beetles in her garden were not a problem anymore and, what's more, her remedy was "organic." The recipe involved grinding up Japanese beetles, with a little soap and water, and spraying this mixture on roses, hollyhocks, lythrum and other plants they favor. Mary Ann dutifully did this, and after a few days, there were still no results. If anything, the beetles proliferated. I asked her how she ground up the beetles. In the kitchen blender, she replied. It cured me of milk shakes for six months, and I lost five pounds. So muck and mysticism aren't all bad.