162 



THE DICTIONARY OF GARDENING, 



Hydnum continued. 



sliced into hot water, and gently pressed, should be care- 

 folly stewed, or rubbed down into a puree. 



FIG. 251. HYDNUM REPA.NDLM. 



HYDRANGEA (from hydor, water, and aggeion, a 

 vessel; in allusion to the cup-shaped fruit). STN. 

 Hortensia. OBD. Saxifrage OB. % A genus consisting of 

 thirty-three species of greenhouse or hardy, deciduous or 

 evergreen, showy shrubs or trees, natives of Eastern 

 Asia, Java, the Himalayan Mountains, North-west and 

 South-east America. Petals four or five ; calyx superior, 

 five-toothed ; stamens eight to ten ; capsule membran- 

 aceous. Leaves opposite, petiolate, persistent or deciduous, 

 entire, serrate, or lobed. Hydrangeas are of easy cul- 

 ture, and are exceedingly ornamental for conservatory, 

 room, or window decoration. They are also well adapted 

 for growing in the open ground, in all the warmer parts 

 of the country. The sorts having abortive or sterile 

 flowers, with an enlarged calyx, are the most orna- 

 mental, and are extensively grown. H. hortensis, and 

 some of its varieties, have nearly all sterile flowers, 

 and are, consequently, most popular. H. paniculata 

 grandiflora is very handsome, and amongst the best, 

 either for pot culture or for outside treatment. The 

 American species are hardier, but not so ornamental, 

 as those from China and Japan. Propagation is readily 

 effected from cuttings of young or partially - ripened 

 shoots, which may be inserted at almost any time when 

 they are procurable. Old plants may also be divided for 

 propagation. For culture outside, a somewhat sheltered 

 position should be selected, except in favourable localities. 



Cultivation in Pots. Hydrangeas may be propagated 

 annually to produce one head of flowers each a method 

 largely practised or they may be grown as shrubby 

 plants several years in succession. Cuttings should be 

 inserted in small single pots, and plunged in a close, 

 warm frame. They may be taken in spring, from young 

 growths that are not bearing flowers, and be grown on 

 throughout the summer, and well ripened in autumn by 

 exposure outside. Another plan is to let the old plants 

 grow all the season, and put in strong points as cuttings 

 when partially ripened. In this case, the formation of 

 roots only should be encouraged, by plunging in a little 

 bottom heat, but not in an inclosed frame. Select the 

 tops of the strongest and most prominent shoots for 

 cuttings, and insert them in August. "When they are 

 rooted, gradually harden off, and expose them to full 

 sunshine and plenty of air in autumn, to insure thorough 

 ripening. When the leaves fade, water should be with- 

 held, and the plants kept dry, in a cool greenhouse, all 

 the winter. In February, or earlier if desired, they 

 may be potted into 5in. or 6in. pots, and started by 

 placing in a higher temperature, and applying more 

 water. The embryo buds, formed the previous autumn, 

 will soon begin to expand; but it is not usual for all 



Hydrangea continued. 



to flower, as they may not have been sufficiently strong. 

 As a rule, the corymb of flowers appears after the 

 fourth pair of leaves; and should the plant develop so 

 far without the embryo being seen, it may be thrown 

 away, unless required for another year. Late antumn- 

 struck cuttings produce useful dwarf-flowering plants 

 in spring, not exceeding 1ft. in height. Those propa- 

 gated in spring, and grown on in pots for the next 

 year, are much stronger and taller in proportion. A 

 new stock should be propagated annually, and the old 

 ones thrown away, unless required for bush specimens 

 or for supplying cuttings, when they may be cut down, 

 repotted, and grown on in pots, or be planted out in 

 the open air. Hydrangeas like a rich soil, such as loam 

 and decayed cow or other manure in equal parts. Any 

 quantity of water may be applied in the growing 

 season; and artificial manure, given just as the flowers 

 are developing, invariably proves beneficial. The flowers 

 sometimes turn blue, certain soils having the property 

 of changing the normal colour, in consequence of the 

 presence of some chemical constituent. Water, in which 

 alum has been dissolved, is used artificially to cause the 

 same change in colour. Iron in small quantity, as well 

 as some other substances, mixed with the soil, are said 

 to produce the same effect. In some gardens, plants 

 that produce red flowers one year may develop blue 

 ones the next, and this without any influence or skill 

 on the part of the cultivator. 



H. arborescens (tree-like), fl. white, small, having an agreeable 

 odour, nearly all fertile ; corymbs flattish. Summer. /. ovate, 

 rather cordate ; upper ones lanceolate, coarsely toothed, pale and 

 puberulous beneath. A. 4ft. to 6ft. North America, 1736. 

 Hardy. (B. M. 437.) 



FIG. 252. HYDRANGEA HORTEXSIS. 



H. hortensis (garden).* Common Hydrangea, fl. varying much 

 in colour (according to the soil in which the plant is grown), dis- 

 posed in ample corymbs or cymes, all diffonned ; fertile flowers 

 few. April to September. I. broadly-ovate, serrated, acuminated. 

 h. 2ft. to 3ft. China, 1790. SYX. Hortetisia opuloides. See 

 Fig. 252. The varieties of this species are numerous; one of 

 the most noteworthy being " Thomas Hogg," a form with pure 

 white flowers. 



H. h. japonlca (Japanese), fl. blue, white, difformed ; cymes 

 crowded. I. ovate-oblong, acuminated, finely an<l glandularly 

 serrated, glabrous. A. 3ft. Japan, 1843. The variety roseo-alba 

 has the outer flowers only radiate, and either white or rosy 

 toothed petals ; and ccerulescens has bright blue ray-flowers. 

 There are also forms having leaves with gold and silver varie- 

 gation. 



