188 JOUBNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



WATER-PLANTS. 

 By F. W. Moore, A.L.S., V.M.H. 



[Read August 3, 1909.] 



" All plants require water." This may seem a trite observation to start 

 with. Everyone will naturally say, "We know that." Nevertheless a 

 suitable supply of water is one of the great difficulties of plant growing, 

 and one which gets far too little attention from careless cultivators. There 

 is no more difficult operation in gardening, nor one which requires more 

 thoughtful skill, than the proper watering of plants. It soon becomes 

 evident that some plants require more water than others ; that what is 

 poison for one set of plants means happiness for another set. Even to 

 the unobservant this becomes obvious in a hilly district. By the dusty 

 road side on the higher levels plants flourish, restricted in growth, harsh 

 in appearance ; even in cracks in dry walls plants grow. On descending 

 to the flats, flats which in winter are occasionally covered with water for 

 a considerable period, vegetation becomes ranker and more varied, and 

 finally pools, ponds, or lakes appear in which plants also flourish. 



In my remarks on " Water-plants " I intend to include all plants which 

 will grow in a saturated rooting-medium, and not merely plants which grow 

 in water partially or completely submerged, thus including what are gene- 

 rally known as bog plants. The term " bog plants " is not a very happy 

 one, as it does not discriminate between peat and mud. In Ireland it is 

 generally applied to peaty swamps in which vegetation is sparse and rather 

 limited, whereas in mud bogs the vegetation is more varied. I consider 

 that any plant which will grow in water or in the saturated margins of a 

 pond, sometimes spreading into the water, and which can withstand being 

 submerged for days, or even weeks, without injury, may be termed a " water 

 plant," just as appropriately as a plant which actually lives in the water. 

 Experiments made at Glasnevin prove that the list of such plants is far 

 more extensive than one would think. It includes many of the Primu- 

 las, Irises, Trollius, Lobelias, and other subjects often grown in the herb- 

 aceous borders. Not only do such plants survive after being submerged 

 for some time, or even covered with a sheet of ice, but they flourish in a 

 way one rarely sees under ordinary conditions. A list of plants which 

 have been cultivated under such conditions, and which during the spring 

 were covered with water for over a fortnight, part of the time quite frozen 

 over, is given at the end of this paper. 



I feel that some apology is due for introducing the subject of this 

 lecture, as it is no new one to the members of our Society. Twenty- 

 eight years ago, September 8, 1881, Mr. George Paul read a very in- 

 teresting paper, entitled " Hardy Water and Bog Plants," in which he 

 described tho water and bog gardens made by him, and gave a useful list 

 of plants suitable for the purpose ; and Professor Boulger on June 19, 

 1900, dealt with the morphological and physiological peculiarities of 



