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226 MAY

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H alesia diptera
Var. magniflora

Roy Lancaster and silverbeils in .VIa_v

IT WAS LIKE NO OTHER fruit I had ever
seen, brown and pear-shaped. about -lcrn fI%in,i
long, with a short slender beak and four wings
running lengthwise. Hundreds of these rather
woody objects hung singly or in bunches along the
previous year’s shoots of a low, vide-spreading,
multi-stemmed tree growing in a wooded enclos-
ure at Rivington near Horwich in Lancashire.
The year was 1955 and, with a bird-watching
friend, I discovere the tree while on a winter

Walkabout in the Pennines. I later identified it as
the Carolina silverbell or snowdrop tree, Halesia
carolina /zezrapzeral and concluded that it must
have been planted in this apparently wild site

 

during the construction. which took place earlier
this century, ofthe nearby Rivington gardens for
the then Lord Leverhulme.

There is something very special about unusual
plants seen for the first time when you are young
or new to gardening and ever since that bright,
clear, finger-numbing day I have had a particular
affection for this hardy. deciduous tree. A few
years ago. I raised a nice strong specimen from

‘.992 2':-IE GARDEN

wild-collected seed. When I realised that my
garden was too full to do it justice. I gave it to a
neighbour so that I might continue to enjoy its
progress. Halesia carolina is one of a small genus
of deciduous trees whose chief merit lies in their
white or pink tinted bell-shaped penciulous flowers
borne from the leaf axils of the previous year’s
shoots in May. These are followed by winged
fruits which offer a ready means of increase.

In the same family as Styrax, the genus corn-
prises only five species (a sixth, H. grandzfolia is
sometimes recognised), all but one native to the
south-eastern United States. The exception is
Halesia macgregorii from eastern China. Of the

Halesia diptera var. magniflora.
The flowers (left) are around
twice the size of the species and
copiously produced in May.
There is a specimen (below) in
the Sir Harold Hillier Gardens
and Arboretum. near Romsey.
Hampshire. now 5m high with a
7m spread

 

 

 

American species H. carolina and H. morzricola are
well represented in British cultivation. the latter.
especially in its variety -vestiza which sometimes
has pink-flushed flowers fforma rosea.-, being
marginally more popular because of its larger

The Revd Dr Stephen
.-sales 1677-1761.
after whom Hales/"a
was named by
Linnaeus. was noted
for his important
experiments in plant

flowers. It also makes a larger tree. especially in
the wild where specimens 24~—30m fi80—lO0ft: are
recorded. although a tree of 16m 52ft"; is the
current champion in Britain.

Of the remaining two silverbells. H. paruflora,
a rare species in the wild, is just as rarely grown
here and because of its supposedly inferior merit
is unlikely to replace H. Carolina and H. monzicala.
which are better garden plants anyway. That
leaves H. diptera which. as the name suggests,
differs from all others in its two-winged fruits.
This last species is uncommon in British
cultivation where it makes a large shrub, 2.5-4.5m
(8-15ft‘) high, or a small tree. It is perhaps the
species most suited in size to the smaller garden
but is also less reliable in flowering and not
entirely hardy in colder areas of Britain.

There is, however, a variety of H. diptera called
magmfiora (large-flowered), which though rela-
tively unknown in British cultivation is proving,
where it does grow, to be a far better garden plant.
A plant in the Sir Harold Hillier Gardens and
Arboretum near Romsey in Hatnpshire has grown
to 5 X 7m (16 X 23ft) since it was planted around
1970 and in May floods its branches with glorious
white flowers. These are around twice the size of
the typical tree, from 2—3cm long.

Its more reliable performance here is probably
due to its habitat in the wild. Typical H. diptera
occurs in flood plain woodland in South Carolina,
Georgia, Florida, Alabama and Texas, while var.
magmflora with a more restricted distribution in
northern Florida and eastern Alabama is found in
deciduous woodlands of upland or ravine slopes.

How the variety magmfiora came to be in
British cultivation is not recorded, although
the Hillier plant (three were originally planted)
originated in the Arboretum Kalmthout,
Belgium, where there is a twin-stemmed
specimen of 10m (33ft). This was already
flourishing in 1952 when Robert and George de
Belder bought the property, soon to be joined by
Jelena (of Hamamelis fame) who became Robert’s
wife. The site was then occupied by a small, badly
neglected arboretum planted in 1857 by Charles
van Geest, an Antwerp nurseryman, and carried
on by Antoine Kort. The only nursery record
remaining dating from 1929, simply lists the
Halesia as a new introduction.

In the arboretum of the Vilmorin family at
Verriers-le-Buisson near Paris grows another
Halesia originally catalogued as H. diptera. but
which M de Belder believes also to be magmflora.
It could well be that there are further old intro-
ductions of this splendid snowbell in Continental

llllb

physiology

 

estates. masquerading, perhaps. as H. dipzera.

Given its undoubted merit there seems no
reason why it should not be made better known.
According to master propagator Peter Dummer.
recently retired from the Hillier Nurseries, it can
be increased by grafting on to H. Carolina or H.
morzticala 1, seed. layering or soft-wood cuttings.

No less fascinating is the origin of the generic
name Halesia, named in honour of the Revd Dr
Stephen Hales which means that the generic name
is correctly pronounced Hale-sia, not Hal-ee-
sia as is normal in gardening circles. According
to Professor Steam / A Gardener’: Dictionary of
Plant Names/, Hales (1677-1761), curate of
Teddington, near London, was a physiologist,
chemist and inventor whose wide-ranging
curiosity resulted in important and far-reaching
experiments in plant physiology as well as,
possibly, the first measurement of blood pressure.
Gardeners may well wonder what connection this
extraordinary man and his experiments had to do
with a beautiful flowering tree from America. The
answer is probably none but Linnaeus, who
established the genus and named the first (type)
species H. carolina in 1759 (two years before
Hales’ death), was persuaded to honour him
thus at the behest of London merchant John
Ellis, one of his correspondents. Ellis (1705-
1770), who knew Hales and admired his work,
was a Fellow of the Royal Society and an
accomplished naturalist, botanist and gardener.
He corresponded with many notable botanists
and horticulturists of his day, including Dr
Alexander Garden of Charleston, South Carolina
from whom he received in 1756 the original
specimens and plants of Halesia carolina.

Those wishing to grow the snowbells will find
them relatively easy, enjoying most a‘ well-
drained soil that does not dry out in summer.
Although woodland trees in the wild, they flower
best here given a sheltered but sunny position.

My thanks to the following friends who kindly provided me
with information for this article: Robert de Belder. Allen
Coombes (Sir Harold Hillier Gardens and Arboretum).

Peter Dummer. Harry van Trier (Arboretum Kalmthoutl and
Marilyn Ward (Kew Library).

: Roy Lancaster. VMH. plarzzsman, lecturer, writer and
broadcaster. is a member of the RHS Floral Committee
B. He has introduced many plants to cultivation from his
travels abroad. especially from China.

THE GARDEN wxv 1992 227