PRIMULA 



PRIMULA 



2783 



also have the proceedings of the Primula Conference 

 held in London in 1913, comprising botanical and hor- 

 ticultural discussions (Journ. Roy. Hort. Soc. 39). 

 The discussion contains a full synonymy of the Chi- 

 nese and other Asiatic species by Balfour and of 

 European species by MacWatt. For cult, and horti- 

 cultural descriptions (for England), the reader should 

 consult H. M. Paul, "Handbook of the Hardy Primula," 

 1911. For evening primrose and Mexican primrose, 

 see (Enothera. 



Notwithstanding the volume of the recent litera- 

 ture, a comprehensive monograph is still lacking, due 

 to the great extension of the genus by contemporary 

 explorers. Further collecting in the Himalaya-Thibet- 

 China region will undoubtedly discover many more 

 forms. The numbers of new species have made it 

 necessary- to extend and to recast the sections as 

 defined by Pax <t Knuth; but these have not yet been 

 redefined and keyed at once in a connected treatment for 

 the entire genus, and in a compilation like the present 

 it is necessary to spread the Paxian groups as a tentative 

 expedient, even if species of not very close relationship 

 are brought together; in this compilation, the purpose 

 is not so much to show botanical affinities as to make an 

 effort to enable the consultant to identify given species. 

 Even so, it can not be expected, in a genus so large, so 

 variable, and in which so many of the species are 

 recently discovered and little known, that the groups 

 and keys will be always satisfactory to the student. 

 Much change is likely to take place in the definition or 

 recognition of species in the genus, as the many forms 

 are more closely studied. In the present account, the 

 characterizations of the species have been drawn so far 

 as possible from the recent working authorities. The 

 portraits are cited in the text under the names they 

 bear in the different publications, and the author can- 

 not vouch for the authenticity of all of them. The 

 reference R. H. S., in the citation of portraits, is to the 

 Journal of the Royal Horticultural Society. 



The date of introduction, given for some of the 

 recent species, is the year in which they were brought 

 into cultivation in Great Britain. The informal notes 

 on culture, under the different species, apply mostly to 

 Great Britain. 



Primulas are cool -climate or cool-season plants, 

 mostly spring-bloomers. Many of them grow at very 

 high altitudes, and depend on very special conditions for 

 their perfect development. Several cultural groups of 

 primulas may be recognized: (1) The alpine and sub- 

 alpine section affords some of the most useful plants for 

 rock and alpine gardens. The relatively little atten- 

 tion given to alpine gardens in this country is the 

 reason for the neglect of these charming spring-flower- 

 ing plants. In recent years, many species have been 

 added to these outdoor primulas and great interest has 

 arisen in them abroad. (2) The polyanthus class, com- 

 prising fully hardy spring-flowering plants, suitable for 

 culture under ordinary garden conditions, and always 

 popular in this countn'. To the same class belong 

 the true cowslip (P. veris) and the oxlip (P. elatior), 

 but these are rarely seen in our gardens in then- 

 pure form. All are easily propagated by division. (3) 

 Yellow-flowered or purple-flowered verticillate-clus- 

 tered outdoor species, of the P. imperialis and P. 

 japonica type, some of which are hardy even in the 

 northern states with some winter protection. (4) The 

 true greenhouse species, represented by the old P. 

 sinensis (Chinese primrose), the more recent P. obconica 

 and the still more recent P. malacoides. These are Chi- 

 nese species. The colors are of the cyanic series. (5) 

 The auriculas of gardens, developed from P. Auricula. 



In Great Britain, much interest is now taken in 

 new primulas, and very many species are more or less in 

 cultivation, the larger part of them as fancier's sub- 

 jects. Not many of them have been tried to any extent 

 in this country, and it is commonly assumed that the 



American hot summers are against them. Many of 

 them are easily grown from seed and can be carried over 

 in pots in a frame, if they are not hardy or will not with- 

 stand the changeable conditions of the open winter. 

 Some of the species do well in open light, but the larger 

 number of the new kinds probably require protection 

 from sun; the species demand an equable supply of 

 moisture. Some of the species mentioned in this coun- 

 try for outdoor growing are P. Auricula, P. Bee&iana, 

 P. Butteyana, P. capitala, P. cortusoides, P. denticulata, 

 P. farinosa, P. frondosa, P. japonica, P. marginata, P. 

 minima, P. pulverulenta, P. rosea, P. Sieboldii, P. 

 sikkimensis, P. Veitchii, aside from the English prim- 

 roses, oxlips, and cowslips (P. acaulis, P. elatior, and 

 P. veris), and the auriculas. For the cultivation of the 

 auricula, see Vol. I, page 430. 



Cultivation of hardy primulas. (E. J. Canning) 



The hardy primulas are not so well known in Ameri- 

 can gardens as they deserve to be, although their cul- 

 ture is gradually on the increase, and new species are 

 occasionally introduced. Perhaps the best known and 

 most commonly cultivated are those which are native 

 to the meadow hinds of Great Britain, central and 

 northern Europe. These are the English primrose (P. 

 acaulis), the cowslip (P. veris), the oxlip (P. elatior), 

 and the polyanthus (P. Polyantha). They are all 

 simple in their requirements, growing and flowering 

 freely in any good garden soil, and are quite hard}' as 

 far north as Massachusetts at least, provided they are 

 not planted in a too exposed or wind-swept position. 

 They are all very attractive when in flower, and they 

 can also be grown in pots and easily forced for flowering 

 in the greenhouse in February and March. 



These primulas may be propagated by seeds or 

 division. Seeds may be sown in February in pans or 

 small shallow flats in a mixture of loam, leaf-mold, and 

 sand of about equal proportions, making the surface 

 very- fine, pressing the seeds evenly into the soil and 

 covering with about ^ inch of the finely sifted mixture. 

 Place the flats or pans in a warm greenhouse or a 

 temperature of 55 to 60 at night with a rise of 15 by 

 day. In two or three weeks the seedlings should begin 

 to appear. As soon as large enough to handle, they may 

 be pricked out into other flats in a similar soil, and 

 about 2 inches apart each way. By the middle of May 

 they will be good plants, and since they do not flower 

 the first season, they may be planted out in lines in 

 some sheltered part of the garden till September, when 

 they may be lifted and planted where they are wanted 

 to flower in spring. Also those intended for flowering 

 in the greenhouse should be potted at this tune. Seeds 

 may also be sown in a coldframe in April or May, scat- 

 tering them very thinly in shallow drills, watering and 

 keeping free from weeds in the summer, and transferring 

 them in September to the position in the garden where 

 they are to flower in the spring. 



Propagating by division is practised when the plants 

 become rather large or to perpetuate some very fine 

 variety. It consists simply in dividing the plant or 

 clump into two or more parts and replanting again. 

 September is the best month to do this. 



The cowslip, oxlip, and English primrose are excel- 

 lent subjects for massing or naturalizing in open wood- 

 land, on sheltered banks, or any position where they 

 are not too shaded, and where they can be left undis- 

 turbed for several years. They are almost indispensable 

 in gardens where a spring display of flowers is wanted. 

 A light mulching with stable-manure, or in very cold 

 gardens, a few branches of hemlock or pine, is all the 

 winter protection they need. 



Other hardy primulas not so well known as the above, 

 but even more beautiful and showy and some of them 

 of larger growth, are species from China and Japan, 

 some of them from high altitudes in the Himalaya 



