Jour. Roy. Hort. Soc. pp. 315-322 (1900)
HYBRID CLEMATIS
By Mr. A. G. JACKMAN, F.R.H.S.

THE hybridisation of the Clematis can be traced back to sixty-four years ago, the earliest successful attempt being made by the late Mr. Henderson, of Pine Apple Nursery, in 1835, who raised C. Hendersoni, which was at that time considered a great acquisition. Its parents are supposed to be C. Viticella and C. integrifolia.

A few years after this saw the advent of C. patens from Japan, which may be taken as the type of the large spring-flowering Clematises, followed by C. Amalia, C. Louisa, C. Monstrosa, and C. Sophia, all of them being varieties of C. patens.

It is to Fortune that the horticultural world next became indebted for sending over from China in 1851 that grand plant, C. lanuginosa, and in 1868 C. Fortunei and C. Standishii, as it is from these three and C. patens that the magnificent large-flowered varieties have been obtained.

The first person to take up the hybridisation of the aforementioned species in this country was Mr. Anderson-Henry, of Edinburgh, who in 1855 crossed C. patens with C. lanuginosa, the result being a handsome lavender-coloured variety named C. Reginae.

After this came the ever-popular Woking hybrid C. Jackmanni, raised in 1858, which, with C. rubro-violacea, C. Prince of Wales, C. rubella, C. magnifica, C. Alexandra, and C. velutina purpurea, all dark-flowering varieties, were the result of crossing C. lanuginosa by C. Hendersoni and C. Viticella atrorubens. Some of these varieties were afterwards crossed with C. lanuginosa, producing several dissimilar varieties, viz.: C. Mrs. James Bateman, pale lavender; C. Beauty of Surrey, light greyish blue; and C. Lady Bovill, greyish blue; also C. Sir Robert Napier, a rich purple, and C. Thomas Moore, a rich puce-violet.

Following these another batch of seedlings was raised at the Woking Nurseries, and first flowered in 1871, from intercrossing C. patens, C. Fortunei, C. Standishii, and C. Sophia plena, with C. Jackmanni, C. rubella, C. rubro-violacea, and C. magnifica, and also reversing the crossings, some of the offspring partaking of the parents of the patens type, whilst the others took the character of the parents of the Jackmanni and Florida types. Those which partook of the patens type showed great variety of colour, amongst them being C. Fair Rosamond, blush white with wine-red bar; C. Edith Jackman, blush white with broad purplish-rose bar; C. Vesta, white; and C. The Queen, delicate mauve; these four varieties being also sweet scented, which is supposed to be derived from C. Fortunei. There were also C. Lord Derby, bluish mauve; C. George Cubitt, pale lilac mauve; C. Lord Mayo, deep rosy lilac; and C. Stella, pale violet with plum-red bars. Of those of the Florida type are C. Countess of Lovelace, bluish lilac with double Anemone-formed flowers; and C. Unique, pale yellowish green. Amongst those which took the character of the Jackmanni type are C. W. E. Essington, a reddish violet; C. Marquis of Salisbury, a dark plum colour; and C. Lady Stratford de Redcliffe, a slaty lilac.

Still further improvements were made, after these at the Woking Nurseries, in the lanuginosa type, notably C. alba magna, which in my opinion is the finest white in cultivation; C. Mrs. Hope, a beautiful satiny mauve, and C. Blue Gem, a pale caerulean blue, both being bred between C. lanuginosa and C. Standishii; also C. Princess of Wales, a deep bluish mauve; C. Robert Hanbury, a bluish lilac; and C. Duke of Norfolk, a deep mauve.

I might here mention that among batches of seedlings there are generally several which partake too much in colour and general character of one or other of the parents, or are too near other varieties in cultivation, to be of any use.

Among the foremost hybridisers of the Clematis must also be mentioned Monsieur Lemoine, of Nancy, who has raised several good varieties of the patens, lanuginosa, and Viticella types of recent years, more especially of the Viticella type, conspicuous among them being C. candidissima plena, C. Florida pallida, and C. Vestale, of the first type; C. lanuginosa candida, C. lanuginosa nivea, C. Otto Froebel, and C. La Gaule, of the second type; C. Monsieur Grandeau, C. Kermesina, C. La Nancienne, and C. Madame Moser; and the fine double-flowered variety C. Lucie Lemoine, of the Florida type. He is also to be credited with several varieties of the herbaceous race.

Next come Messrs. Simon Louis, of Metz, their earliest varieties being likewise improvements on C. patens, viz.: C. Louisa plena, C. Clara, and C. Marie; they afterwards brought out C. splendida, C. fulgens, C. perfecta, and C. nigricans, the first two being raised from C. lanuginosa crossed with C. Viticella grandiflora.

Messrs. Cripps & Son have also introduced several good varieties, principally of the lanuginosa type. I am not acquainted, however, with any specific crosses they have made, but amongst the varieties raised by them, C. Lady Caroline Nevill, C. Madame van Houtte, C. Tunbridgensis, C. Star of India, and C. Fairy Queen still retain honoured places in good collections.

Another eminent hyhridiser is. Mr. Charles Noble, who has raised several varieties, principally of the patens type, from the intercrossing of C. Standishii and C. Fortunei, chief amongst them being C. Albert Victor, C. Miss Bateman, C. Lady Londesborough, C. Lord Londesborough, and C. Mrs. Villiers Lister.

Other names associated with the fertilisation and improvement of the Clematis are: Messrs. G. Baker & Son, who raised C. Gem from C. lanuginosa crossed with C. Standishii, which is almost identical with C. Reginae, raised by Mr. Anderson Henry some years previously, as already mentioned:— Messrs. Richard Smith & Co., who raised C. Beauty of Worcester and C. Snow White Jackmanni:— Mon. Briolay-Goiffon, who raised C. Aureliana from C. patens crossed with C. lanuginosa:— Mon. Rinz, of Frankfort, who obtained C. Francofurtensis from C. patens crossed with C. Viticella caerulea:— Mon. Carré, of Saint-Julien, who introduced C. Gloire de St. Julien and C. Impératrice Eugénie, the result of crossing C. monstrosa plena with C. lanuginosa pallida:— Mon. Dauvesse, of Orleans, who raised C. Jeanne d'Arc from C. palans crossed with C. lanuginosa:— Mon. Modeste-Guérin, who sent out C. modesta, from C. lanuginosa crossed with C. Viticella, and C. purpurea hybrida:— Mon. Christen, of Versailles, who raised C. Etoile de Paris, C. La Géante, and C­Madame Furtado-Heine, the latter being a cross between C. Viticella rubra grandiflora and C. lanuginosa:— Mon. F. Morel, of Lyon Vaisse, who introduced C. Etoile Violette, C. François Morel, and C. Perle d'Azur, and has recently raised several new varieties of the Viticella type:— Mon. Baron Veillard, who obtained C. Madame Edouard André by crossing C. Jackmanni with C. patens, and C. Madame Baron Veillard:— and Mon. Gegu of Angers, who raised C. La France by crossing C. lanuginosa with C. Jackmanni.

Nearly all the varieties mentioned as having been raised in this country were obtained previous to 1880; since then the introduction of really sterling new varieties has been almost nil—in fact, successful hybridisation or cross-breeding of the Clematis appeared to be practically at a standstill for about twelve years, until it was revived by the introduction of my new race of hybrids, which were obtained by crossing C. coccinea, one of the small American species from Texas, with the large-flowered garden varieties, the former being the pollen parent. This cross had previously been tried in reverse order without any result. There were, I think, two reasons for this falling-off in the raising of improved varieties of hybrids. It was due mainly, I think, to the want of fresh blood on and with which to work. Hybridising and intercrossing amongst the large-flowered species and their hybrids—including not only an almost overwhelming number of varieties of nearly all shades of white, mauve, lavender, lilac, blue, purple, and violet, but embracing a continuous flowering season from May to October—had been carried on to such an extent that it became very difficult, if not impossible, to obtain anything really distinct. Secondly, the only too well known "dying off" amongst the Clematis rendered cross-breeding very disappointing, as unless great care was taken in selecting robust parent plants which had not shown any signs of this "dying off," failure and disappointment would most probably ensue, either in the loss of the seed-bearing parent, or in handing down to the offspring the evil which had been engendered in the parent.,

The cross-breeder, before starting to work, should first decide upon what qualities or points he wishes to develop in the offspring, and see that at least one or both of the parents possess similar characters, and that, besides being of sound and robust constitution, they have flowers of good form and habit for their respective types; the latter is a point which has often struck me as being wanting, especially in some of the continental varieties, so many of them having long and narrow sepals, giving a decidedly weak and starry appearance to the flower.

I have noticed from time to time the different opinions expressed, through the press, upon the cause of this "dying off," the most recent being by certain continental gentlemen in "The Garden" of February 18, 1899, in which Messrs. Goos & Koenemann give their opinion that it is caused by the bunting of the cells through excessive moisture. Mr. J. Nicolai believes it to be caused by injury from frost; Mr. C. A. Meyer thinks it is brought about by too rich food or too much water; and Professor Dr. P. Soraner, that too much water, nourishment, and heat are the cause. All these gentlemen are to a certain extent right, as there is no doubt in my mind that frost is the cause in some cases, too much water and bad drainage in others; butin my opinion they have not yet arrived at the principal reason, as I have seen plants affected which have never been touched by frost. And my experience is that plants mostly go off during the summer months, when the ground is driest and the temperature hottest; and in most of these cases I could not detect any sign of the plants having had too much moisture, or that the drainage was bad. In addition to this, the collapse often comes after the plant has made several feet of growth, and is forming the flower buds; which to me seems to imply that its vital power had been expended, the result being a speedy and total collapse. Besides, if the reasons given by these gentlemen are the only and right causes, how is it that this "dying off" was not noticed twenty-five and thirty years ago, and why should it have increased of recent years? Again, how is it we do not see the rampant robust growths each year which there used generally to be? Putting on one side for a moment the fact that the Japanese and Chinese species have not the stamina of some of the European, American, and other species, there seems to me but one answer to all these queries-viz. that the Clematis is suffering from loss of constitution through over-propagation; and that is, in my opinion, to a great extent the cause of the "dying off," for it has been conclusively proved that neither insects nor fungi are responsible for it. Assuming that this is correct, we have at once the cause of some of the disappointments and failures in raising new hybrids in past years, and the reason why several of the newer varieties are affected in the same way.

With regard to the new race of coccinea hybrids already mentioned, several seedlings have been raised, from which I have at present selected the following varieties, showing great diversity in colour and form from any other hybrids, as well as improved constitution, which were the objects aimed at in making the cross. They are C. Countess of Onslow, a bright violet purple; C. Duchess of Albany, a beautiful bright pink; C. Duchess of York, a pale blush pink; C. Grace Darling, a bright rosy carmine; C. Sir Trevor Lawrence, a bright crimson; and C. Admiration, a rich magenta purple. These new varieties also lay claim to profuse and successional blooming properties, more graceful habit, greater substance in the sepals of the flowers, which, in conjunction with their being produced on long peduncles, renders them of great use for decoration.

The following is a table of several specific crosses made between species. and species and hybrids. Unfortunately no records have been kept of the parents of several of our best hybrids; consequently I am unable to trace the improvements made to any great extent.

I will commence with

C. patens (mauve lilac) x C. lanuginosa (pale lavender)
producing C. Aureliana, porcelain blue;
C. hybrida Andegavensis, dark blue;
C. Baraillet Deschamps, mauve;
C. Reginae, lavender blue;
C. Jeanne d'Arc, greyish white;
C. Otto Froebel, greyish white;
C. lanuginosa nivea, white;
C. lanuginosa candida, white;

the first two partaking of C. patens; Baraillet Deschamps, which is a double-flowered variety, being classified amongst the Florida type; and the last five, which are all whites with the exception of C. Reginae, resembling C. lanuginosa.

Next we have

C. lanuginosa nivea (white) x C. lanuginosa (pale lavender)
yielding C. Duchess of Teck, white;
C. Duke of Richmond, lavender grey;

 

and C. lanuginosa nivea (white) x C. Standishii (light blue mauve)
  producing C. Earl of Beaconsfield, deep mauve;

 

also C. lanuginosa candida (white) x C. Standishii (light blue mauve)
  giving us C. Florence, pale mauve;

all of these pertaining to the lanuginosa type. And from

C. lanuginosa candida (white) x C. Fortunei (creamy white)
we have C. Mrs. George Jackman, white;
C. Belle of Woking, silvery grey;
C. Petrarch, creamy white;

the first belonging to the patens type, but continuing in flower much later than most of that type; the second partaking of C. Fortunei, and classified under the Florida type; and the last being of the lanuginosa type.

Next, from C. patens (mauve lilac) x C. Fortunei (creamy white)
  is derived C. Lucie Lemoine, white,

a double variety of the Florida type.

 

From C. patens (mauve lilac) x C. Viticella (bluish, purple, or rose)
  we find C. Guascoi, deep purplish violet;

 

and from C. patens (mauve lilac) x C. Viticella caerulea (blue)
  we have C. Francofurtensis, deep purplish blue;

both of the Viticella type.

Also, from C. patens (mauve lilac) x C. Jackmanni (violet purple)
  we have C. Sabrina, pale lavender;
C. Lord Lytton, bluish purple;
C. The Kelpie, grey;
C. The Kelpie's Bride, white;
C. Mdlle. Torriani, solferino pink;
C. The Czar, purple;
C. The President, dull violet;
C. Madame Edouard André, dark red;

these, as will be noticed, showing great diversity of colour—the first five partaking of the parent patens, and the last three of the parent Jackmanni.

I will next take the other crossas made with C. lanuginosa. First we have

C. lanuginosa (pale lavender) x C. Fortunei (creamy white)
giving us C. Mrs. G. Mitchell Innes, pale lilac mauve;
C. Thomas Tennent, French white;
C. Mrs. Melvill, pale mauve;
C. Symeana, pale mauve; C. Henryi, white;
C. Lawsoniana, rosy purple;

the first two resembling C. Fortunei, and therefore classed under the Florida type, and the last four partaking of C. lanuginosa.

Next we have

C. lanuginosa (pale lavender) x C. Standishii (light blue mauve)
producing C. Duke of Norfolk, deep mauve;
C. Blue Gem, caerulean blue;
C. Gem, deep lavender;
C. Mrs. Hope, satiny mauve;

all of these clinging to the parent C. lanuginosa. Then

C. lanuginosa (pale lavender) x C. Viticella (bluish purple or rose)
yielding C. Viticella amethystina, pale violet blue;
C. Viticella pallida, lilac;
C. Modesta, bright blue;
C. Madame Grangé, deep maroon crimson,

all of the Viticella type;

C. lanuginosa (pale lavender) x C. Viticella grandiflora (blue)
giving us C. fulgens, dark mulberry purple;
C. splendida, rich reddish violet;

being intermediate between the two parente, and classified under the Jackmanni type; and

C. lanuginosa (pale lavender) x C. splendida (rich reddish violet)
producing C. lanuginosa perfecta, violet mauve.

Next, from

C. lanuginosa (pale lavender) x C. Viticella rubra grandiflora (claret crimson)
we have C. Madame Furtado-Heine, satiny rose,

also intermediate between the two parents, and classified with C. Jackmanni.

From C. lanuginosa (pale lavender) x C. Jackmanni (violet purple)
  we get C. La France, deep violet blue,
C. Reine des Blues, blue,

both of the lanuginosa type. And from

C. lanuginosa (pale lavender) x C. rubro-violacea (maroon purple)
we have C. lanuginosa violacea, bluish purple.

 

Also, from C. lanuginosa (pale lavender) x C. Fair Rosamond (blush white)
  we find C. Ville de Parie, flesh-coloured white,

likewise of the lanuginosa type.

Then we have

C. lanuginosa pallida (pale lavender) x C. monstrosa plena (white)
producing C. Gloire de St. Julien, French white,
C. Impératrice Eugénie, pure white,

both of the lanuginosa type;

C. Fortunei (creamy white) x C. Standishii (light blue mauve)
yielding C. Princess Mary, pale pink,

of the patens type;

and

C. Fortunei (creamy white) x C. Jackmanni (violet purple)
giving us C. Xerxes, dark violet;
C. Zanoni, mottled lilac;
C. Jackmanni alba, greyish white;

all of them belonging to the Jackmanni type.

Next we have

C. Standishii (light blue mauve) x C. Jackmanni (violet purple)
producing C. Earl of Egmont, deep reddish purple,
C. Mdlle. Albani, pale lilac mauve,

both of the latter type. And from

C. Standishii (light blue mauve) x C. John Gould Veitch (lavender blue)
we have C. Lady Alice, deep lilac mauve;
C. Margaret Dunbar, deep purplish lilac;
C. Elaine, violet blue;
C. Undine, rosy lilac.

the first two belonging to the patens type; the other two, which are doubles, being classified under the Florida type.