The long-awaited raised bed article

[McClements, Jim]

Thanks to Bobby Ward, who had preserved my deathless prose, as well as that
of John Neumer, in electronic form, herewith is the information about the
"peat/sand sandwich". I understand that Mike Slater has been using this
concept for a few years and will have something to post on the subject soon.

Jim


Raised Beds for Woodland Gardening
by Jim  McClements

My wife and I have had a gradually enlarging woodland garden for about
fifteen years, containing initially mostly wildflowers of the eastern  U.S.,
but now including many western and Asiatic species. It, therefore, came as a
bit of a shock when earlier this year I found out that I had been doing it
all wrong!
This revelation was the result of reading a summary of  an  article by
John Neumer, of Hockessin, Delaware, the original of which was published in
The Dodecatheon, the newsletter of the Delaware Valley Chapter of NARGS, in
1986, long before I was a member.   I think it will interest any gardener,
but particularly those who struggle in a woodland setting to provide an ideal
situation for plants, free of tree-root competition and providing maximum
organic material combined with good drainage. While my experience with
John's scheme is short, I am much impressed and will describe results thus
far, a few ideas on modifications, and the results of a recent conversation
with its originator.

First, let me insert here the original article by John:

The Peat Bed
by John Neumer

Primulas are worth a little extra effort: a peat bed perhaps? The
British and Louise Beebe Wilder discuss their peat gardens as if  every
garden setting has one, of course. One imagines great borders filled two feet
with peat and sand-borders which certainly I will never have. And then too,
as before every new effort, there is always some doubt. A British gardener
surrounded by chalk requires a verisimilitude of woodland earth; but did
Louise have a similar compelling need? Well, put such doubts to rest. Even a
compromise "peat" bed requiring only modest effort has powers to please that
will astonish even the inveterate gardener. So momentarily stop your labors
of re-creating a mountainside (it will never work anyway) and enjoy the
relative play of establishing a 50 sq. ft. "peat" bed. You will quickly
repeat the effort, but try this modest bed first.
In late fall, preparation begins by selecting a turfed area under high
one-half day shade. Don't touch the turf. Pile oak and other available leaves
to a depth of 1.5-2 ft. over the new border profile, and relax until spring.
Then, with the leaf mass now compressed (an occasional winter stamping
helps), I distribute over the leaves coarse sand and 160 lb. of composted cow
manure. Think of building a layer cake. Sixteen cubic feet of peat and a thin
overlay of coarse sand completes the  effort. Other than spreading the
individual layers more or less evenly, there is no mixing of the layers.
The capping of the bed is done sufficiently early for the spring rains
to wet the bed thoroughly. If I'm ambitious, I add a top cosmetic layer of
woodland scruff, but this is not necessary. The bed is now ready for spring
planting. When planting primulas, I use a collar of loam to anchor them in
the loose bed. This is important, you will see, for winter security. In one
season the bed medium takes on a black color like that seen in wet Rocky
Mountain vales. I never thought that I could find thrills in root structure,
but when you lift a Primula cluster and see the vigor of the white threads
deeply penetrating this black mass, you know you have created a very special
environment. Maintenance is easy; every year I add a thin layer of leaves,
peat and coarse sand.
The bed is also a "natural" for a host of Japanese woodlanders, and for
virtually every other subject which dawdles elsewhere in the rock garden. In
my experience, more "new" gardening goes on in these beds than in the rock
garden proper. This year the peat bed was the first to receive
Boenninghausenia albiflora, and Roscoea alpina seedlings, and here they have
prospered. It is an ideal refuge for Japanese polemoniums, aconitums and
select gentians. The propensity of this bed for accommodation is, I'm sure,
endless; i.e., all young azalea cuttings are given a year of two in the bed
before their final setting. And not least to mention, it is the only proper
home for the phlox woodlanders.
I am ever thankful that a few of the fine Ohio basin woodland phlox
subspecies collected by Rocknoll Nursery persisted in my garden long enough
to find their "proper" home in the "peat" bed. For the first time I now see
them as their genes intended, and what a spectacle it is! For this show
alone, the bed would be worth thrice the effort.
Discovering the peat bed is a little like an artist finally becoming
aware of the medium in which he can express exponential creativity. You come
to realize that almost no area of the rock garden is ideally suited to its
plant inhabitants (the rock wall is the one exception that proves the rule);
most of our subjects merely tolerate their transposed environment and we in
turn are rewarded with struggle and angst. Peat bed gardening by contrast is
natural gardening at its best; it cooperates with all natural tendencies
within the suited subjects. This symbiosis is never better than in the peat
bed. For East Coast gardeners, the rock garden rewards, but the peat bed
rewards overwhelmingly.
A final caveat: the above construction of the peat bed is an evolved
design. At first I dug out a bed and filled the hollow with peat, sand and
manure. This bed gave inordinate heaving of Primulas during winter. Thus the
leaf mold base offers an important root anchor. Nevertheless, even in the new
beds, I also use a loam collar around new sets as additional anchoring
insurance.




Here are my additions and comments:

I started the first of these beds by piling up leaves in December ('95). The
bed was completed in April, in time to receive most of the spring arrivals
from various sources. By the middle of summer, I was so impressed with the
way everything was thriving that I went ahead with another bed, using
left-over mulched leaves from the previous year as the base. Two more beds
have followed, so that I now have four and am searching for areas for more.
Everything has done well: from ferns to  arisaemas to phlox to primula to
trilliums. For instance, in May I transplanted new seedlings of Glaucidium
palmatum, a procedure reputed to be a real "no-no" but better than watching
them damp off, and was gratified to see them all survive. A dwarf  kalmia
bought in Utah and found to have essentially no roots looks as if it may have
a few flower buds for next year. Ferns grown from spore and set out are
almost the size of mature plants, and I can confirm John's observations about
the huge root systems that develop readily in these beds. They are as
valuable as nursery beds for new plants and seedlings as they are for mature
plantings, and should be used both ways.
As for modifications, I have made two. The first is to use a layer of the
woven "weed fabric" under each of the last two beds (under the leaf pile).
This is for further insurance against the intrusion of tree roots,
particularly those of tulip  poplars, which have in the past few years been
the bane of our existence. After years of laboriously digging woodland beds
and chiseling out roots, it dawned on me that what I was mainly doing was
stimulating more  root growth. It is important not  to dig or disturb the
ground where the peat bed is to be located. The bed can be put under a tree,
but should not cover more than a quarter or so of the tree's root area..
My second idea is to use some Turface in the upper layer of sand. I
discussed this with John and he agrees that it might help, particularly if
one can't obtain coarse builders sand. Fine sand is NOT what you want. I
tried to pin John down on the thickness of the various layers, but he
apparently varies that to some extent depending on what he has "lying
around". The bottom sand layer should be about 2 inches, the peat layer 4-6
inches and the upper sand an inch or less. He says that the real secret is to
NOT skimp on the leaves, which will shrink considerably over a few years. His
recommended yearly addition of leaves, peat and coarse sand (or Turface?)
goes on in the late fall after plants go dormant.
I asked if he had rodent problems. The answer was ''no,'' but I have
recently found some vole activity behind the logs that I have been using to
edge the beds. (Without edging they look somewhat as if an elephant has been
recently buried.) I think that the voles will be easily controlled with
poison; but I may be overly optimistic.
My final question to John, who has been using this approach for over ten
years, was about long-term results, problems, and so forth. He is still as
enthusiastic as when he wrote the article, and just completed a very large
peat bed. He does say that some of the beds tend to "peter out" in about five
years, particularly if the initial leaf layer has not been generous enough
and/or if the yearly replenishment has not added enough organic material. In
that case, he transfers the plants to another bed while redoing the first
one.
These beds are easy to construct (especially compared to "double-digging!),
give wonderful results, and should be of special appeal to those who are
forced to garden in clay soils, as are found in Delaware and, as it is
rumored, in parts of North Carolina. They have certainly changed my approach
to gardening.

[Jim McClements and his wife Anne  garden  in Dover, Del.]