A GARDENERS CLASSIFICATION OF CLEMATIS

by Dr John Howells

The Clematis. 1992


INTRODUCTION
The difference between botanists and gardeners is well illustrated by William Robinson's statement "for the botanist all plants are equal. Gardeners must choose between plants or suffer". The one strives for exact knowledge. The other chooses plants for use or effect. I submit that each is correct in his own sphere.
To classify allows objects with similar characteristics to be placed together and in so doing theknowledge of the group is available to illuminate thecharacteristics of the individual object. Thus comes knowledge of everyday value in cultivation and propagation. To the botanist the classification has to be according to strict botanical criteria. Anyone who doubts the value of botanical classification will surely be convinced by the Hibberds paper on the subject. But, for the gardener classification is best in terms that allow him to plan and cultivate with optimum efficiency and effect. It is this type of classification that I would like to pursue here, to quote Moore and Jackman "a system of classification based rather upon cultural than upon botanical considerations".
Clematis, like other objects, could be classified according to colour, height, smell, root structure, etc. But what the gardener truly needs is a grouping of clematis according to general growing characteristics. He needs to know such facts as what have similar general habits of growth, which come early or later, which are large or small flowered.
In gardening books it is usual to classify clematis according to their pruning requirements; so are produced three clematis groups. Group 1 clematis require a tidy only. Group 2 clematis require little pruning. Group 3 clematis require hard pruning. To illustrate how unsatisfactory this classification can be we can focus on Group 3 clematis. Here we find that, other than in its pruning requirements, the herbaceous clematis have nothing in common with the viticellas and they nothing in common with the texensis group or they with the orientalis group.
However, it is of interest that authors, while espousing this pruning classification have also grouped clematis in their written works. Spingarn has six groups: florida, patens, lanuginosa,jackmannii, texensis and viticella. Whitehead lists ten groups: alpina, armandii, florida,jackrnanii, lanuginosa, macropetala, nwntana, patens, lexensis and viticella. Lloyd talks of groups the large flowered hybrids, conservatory clematis, the atragenes, the texens, the viticellas, herbaceous clematis, and late flowering species. Fretwell has two large groupings - the large flowered hybrids and the species with small flowered hybrids. Fisk has a similar large division into small flowered species and large flowered varieties; he sees no value in dividing the latter into lanuginosa, patens and florida groups. Evison classifies clematis under the three pruning groups but when listing clematis he has evergreen types, alpina and macropetala types, montana types, early large flowered cultivars, double and semi-double cultivars, mid season large flowered cultivars, late large flowered cultivars, viticella types, late flowering species. The new RHS Dictionary has the following groups: small flowered species and their hybrids, florida, jackmanii, lanuginosa, patens, texensis, viticella. Grey Wilson and Victoria Matthews, both taxonomists, give the clearest lead in the literature on grouping giving the following: Under Group A, requiring a tidy after flowering, are subgroups montana, alpina, macropetala, armandii, and cirrhosa; under Group B, requiring hard pruning, are subgroups viticella, texensis, jackmanii, vitalba, orientalis and an extra subgroup; Group C consists of the large flowered hybrids. It is of interest that facing the practical task of guiding the buyer, the author of the Plant Finder finds it useful to group clematis. Again, Denis Bradshaw separates the field out into a number of groups when devising a scheme for clematis collections.
The above survey demonstrates the movement away from classifying according to pruning considerations towards a classification based on groups of clematis. In 1990 I suggested an everyday classification for clematis and elaborated further in 1991. Tne latter was the basis of my classification in the "Plantsman's Guide to Clematis" in 199l." Here I would like to elaborate even further so as to stimulate discussion on this topic.


LARGE FLOWERED CLEMATIS
The classification of the large flowered cultivars were traditionally based on the dominant parent in their hybridisation. Thus there were the patens groups which included such as 'Barbara Jackman', 'Bees Jubilee', 'Lasurstern', 'Miss Bateman', etc. Flowering later come the lanuginosa group which include such as 'Henryi', 'Marie Boisselot', 'William Kennett', etc.. The florida group tends to produce double flowers at the first early flowering and single blooms later and includes such as 'Duchess of Edinburgh', 'Kathleen Dunford', 'Miss Crawshay', 'Proteus', etc. Latest of all came the jackmanii such as 'Perle D'Azur' and 'Madam Baron Veillard'. Today all experts are agreed that due to the great interbreeding this classification is no longer useful.
To divide the large flowered clematis into early and late flowering sections seems very justifiable. The early flowering section clematis (patens, florida and languinosa types) produce flowers from ripened stems of the previous season's growth. The late flowering section clematis (jackinanii types) produce flowers from the current season's growth. These facts determine different management, including pruning, for the two sections. Some would argue the further division of early flowering section into an Early Season group (patens and florida types) and the Mid Season group (languinosa types).
Another possible classification of the large flowering clematis can be based on colour. Given a definite colour, such as white or red, grouping is easy. But blues have so many shades that they can be difficult to differentiate in practice. Also shade, sun, age of bloom, and latitude of the garden can grossly affect the colour in a flower.
Some gardeners would be content to list the large flowering clematis alphabetically and then signify alongside the name of the clematis whether it is single or double, striped or not, its colour and approximate time of blooming.
To summarize, it is suggested here that the large flowered clematis hybrids be considered as two sections: EARLY FLOWERING (main flowering from old growth) and LATE FLOWERING (main flowering from new growth).


SMALL FLOWERED CLEMATIS
In general and with a few exceptions, the small flowered species and their hybrids are distinguished from the large flowered by their root system which is not 'lace like'. Here we must attempt to group by the general garden characteristics.
A clematis may qualify to be included in more than one group eg C viticella 'Nana' can be classed under the viticella group or the rockery group, C columbiana var 'Tenuiloba' under the atragene group and the rockery group; this is proper in an utilitarian classification but not permissable in a botanical classification.
To fail to group the clematis has often meant that the virtues of a group has been overlooked. For instance, the failure to identify the rockery clematis has meant virtually no attention being given to this group. Again the virtues of the viticellas have been overlooked because they tend to be grouped with the large flowered clematis and the values of their strong growth and almost disease free nature not brought to notice.
The early groups of the species need little if any pruning; the late groups of the species usually benefit from hard pruning. Thus the species and their hybrids are usefully divided into an early flowering section and a late flowering section.
In the classification that follows the reference in brackets indicates the grouping in the botanical classification by Snoeijer. All his groupings can be included here.


EARLY FLOWERING SPECIES
In order of flowering they are:

1. The Evergreen Group.
This is the earliest group to flower. It includes three sub groups:
A cirrhosa, napaulensis, [Gp IIIB]
B annandii, finetiana, Xjeuneana, meyeriana, quinquefoliolata, uncinata, [Gp IVA 1 -b.]
C New Zealand clematis: afoliala, foetida, indivisa [Gp IIIA4]

2. The Atragene Group.
Pringle's work has helped to clarify the situation here. There are two sub groups:

A. The alpinas which includes cultivars and many hybrids [Gps I.D. and I.C.] such as 'Columbine', 'Frances Rivis', 'Ruby', etc.

B. The macropetalas which also includes cultivars and many hybrids [Gp ID] such as 'Markham's pink', 'Maidwell Hall', etc.

3. The Montana Group. It includes: Montanas with cultivars and many hybrids 'Elizabeth', 'Mayleen', 'Freda', etc; chrysocoma, graciliflora; X vedrariensis, etc. [Gp IIB]

4. The Rockery Group. These flower alongside the above. It could be termed the alpine group but perhaps 'rockery' is to be preferred to differentiate from the 'alpina' group. Any clematis from another group is correct here as long as its growth habit make it suitable as a rockery plant.

It includes: New Zealand plants such as marmoraria, petriei, and hybrids such as X cartnwnii 'Joe', County Park Hybrids, Havering Hybrids [Gp III A.4]. addisonii [Gp Il]. albicoma and columbiana var tenuiloba [Gp ID] and douglasii var scottii 'Rosea' from the USA [Gp ID]; Vilicella 'Nana' [Gp VA]; ranunculoides. Some of these plants can be listed under other groups as well.


LATE FLOWERING SPECIES
There is considerable overlapping in flowering times but in approximate order of flowering they are:

1. Viticella Group. [Gp V A]
It includes hybrids such as 'Abundance', 'Alba Luxufians', 'Etoile Violette', 'Purpurea Plena Elegans', 'MargotKoster', etc. Campaniflora is best listed here. Some would include "Ascotiensis', 'Ernest Markham', 'Lady Betty Balfour', and 'Ville de Lyon' here.

2. Texan or Vioma Group [Gp II]
It includes texensis hybrids such as 'Duchess of Albany', 'Etoile Rose', 'Gravetye
Beauty', 'Sir Trevor Lawrence', 'Pagoda'. Also addisonii, crispa, pitcheri, viorna. Some would include fusca here.

3. Meclatis or Orientalis Group [Gp IE and IF]
Grey Wilson has untangled the situation here. It includes hybrids of tangulica such as 'Bill Mackenzie', 'Gravetye Variety', 'L&S No 13342'. Denis Bradshaw has suggested that to call this group 'yellow flowered' would allow the inclusion of akebioides, brachiata, graveolens, serratifolia, rehderiana, vemayi.

4. Herbaceous and Semi-herbaceous Group
This may be a diverse botanical group but a clematis is included here if its growing habit is more or less herbaceous.
Xjouiniana Praecox; heracleifolia; stans [Gp IB].
integrifolia, eriostemon, durandii [Gp II].
recta [Gp IV I a].

The shorter growing plants such as heracleifolia, stars, integrifolia, and recta can also qualify as rockery clematis.

5. Late Climbing Group
Angustifolia [Gp IV A2]; aethusifolia [Gp IA]; flammiila, maximowicziana [Gp IVA]; phlebantha [Gp III A2]; fargesii, grata, virginiana, vitalba [Gp IIIA]; napaulensis [Gp IIIB]


CONCLUSION
Clematis flower in the following approximate sequence early small flowered species, early large flowered cultivars, late large flowered cultivars, late flowered species. The early flowering clematis, large and small, require little or no pruning; the late flowering clematis, large and small, will stand hard pruning. A division into early and late flowering sections seems appropriate. The small flowered clematis, early and late, can be farther divided into groups.
Final agreement on where every clematis should be listed may be hard to achieve. For instance is 'Pagoda' to be listed in the Texan or the Viticella group? Again Napaulensis can be considered in the late species section or the early specis section depending upon the time of its flowering. In a gardeners classif ication a clematis can be listed in more than one group. Flexibility is an attribute in a gardeners classification; it would be an offence in a botanical classification.


SUMMARY

1. EARLY FLOWERING SECTION

A. LARGE FLOWERED CULTIVARS. (Flowers from old growth)

B. SMALL FLOWERED SPECIES AND THEIR HYBRIDS
I. Evergreen Group
2. Atragene Group
3. Montana Group
4. Rockery Group

11. LATER FLOWERING SECTION

A. LARGE FLOWERED CULIIVARS (Flowers from new growth)

B. SMALL FLOWERED SPECIES AND THEIR HYBRIDS
1. Viticella Group
2. Herbaceous or semi herbaceous Group
3. Meclatis or Orientatis Group
4. Texan or Viorna Group
5. Late climbing Group


REFERENCES
I. BRADSHAW, D. Clematis Collections. 1991. The Clematis. 47.
2. EVISON, Raymond. Making the Most of Clematis. 1991. London. Floraprint.
3. FISK Jim. Clematis: The Queen of Climbers. 1989. London. Cassell.
4. FRETWELL, Barry. Clematis. 1989. London. Collins.
5. GREYWILSON, C. 1986. Newsletter. Int.Clem.Soc. 3.7
6. GREYWILSON, C. and Matthews V. Gardening on Walls. 1983. London. Collins.
7. HIBBERD, Francis and David. Gardeners Versus Taxonomists - An Illusion. 1987. The Hardy Plant. 9. P42,
8. HOWELLS, J.G. An everyday classification for clematis. Letter. 1990. CI.Int. P.45.
9. HOWELLS, J.G. Aneverydayclassification forclematis. Letter. 1991.,MeClematis. P55.
10. HOWELLS. J.G. A Plantsman's Guide to Clematis. 1990. London. Ward Lock.
I I. LLOYD, Christopher. Clematis. 1989. London. Viking.
12. MOORE, J. and Jackman, G. The Clematis. 1877. Woking.
13. PHILIP, Chris. The Plant Finder. 1992. Ashboume, MPC
14. PRINGLE, James S. Clematis Subgenus Atragene. 1991. The Clematis. 4.
15. ROBINSON, William. 'ne Virgin's Bower. 1912. London. John Murray.
16. SNOEIJER, Wim. A suggested classification for clematis. 1992. 'The Clematis.
17. SPINGARN. J E. The Large Flowered Clematis Hybrid. 1935. Nat.Hort.Mag. 14.64.
18. The New RHS Dictionary of Gardening. 1992. London. Macmillan
19. WHITEHEAD. S.B. Clematis. 1959. London. John Gifford.

ACKNOWLEDGENIENTS
Grateful thanks to Denis Bradshaw, Jim Fisk, John Fopma and Wim Snoeijer who commented most constructively on the manuscript. But this does not signify agreement with every element in it.

Please note this web version of this article was scanned and may contain spelling errors, which are in no way the authors.

 



Site created and maintained by Studio 46: jga@Studio46.co.uk