154 



The Heart's ease must be gro-mi in 

 very rich soil, composed, if in pots 

 or boxes, of four parts of rich loam, 

 one of sand and one of decayed 

 leaves or rotten dung ; and if in the 

 open ground, of rich loam highly 

 manured. It is propagated by seeds, 

 or division of the root. The seeds, 

 should be SQ-wn as soon as they are 

 ripe in a bed, where the young plants 

 should remain till they flower, when 

 the best should be taken up and re- 

 planted in another bed, or in well- 

 drained pots or boxes, for flowering. 

 The plants will require constant wa- 

 tering during the hot weather ; but 

 they are very apt to damp off, if the 

 soil in which they grow has not been 

 well drained. The best varieties are 

 propagated by cuttings taken off from 

 the points of the shoots, in the spring, 

 cuttingthem clean across immediately 

 below a joint. The cuttings should 

 be struck in pure white sand, and 

 covered with a bell-glass ; they should 

 not be watered when put in, and they 

 should be shaded for several days. 

 Heart's-eases^are also propagated by 

 layers, pegged down at a joint, but 

 not slit, on account of their tendency 

 to damp off. 

 ' Heat is concentrated or produced 

 in gardens in a variety of ways : by 

 shelter from winds, which prevents 

 the natural heat of plants from being 

 carried off by cui-rents of air passing 

 over them ; by exposure to the sun, 

 which concentrates its ray s ; by cover- 

 ing a surface of soil or the roots and 

 stems of plants with anon-conducting 

 material, such as straw, litter, leaves, 

 &c, , which prevents its radiation ; by 

 fermenting substances, such as stable- 

 dung, litter, leaves, tan, &c., which 

 produce heat by their decomposition; 

 and by the consumption of fuel, from 

 which the heated air generated is 

 conducted in flues, or by means of 

 pipes of hot water or steam. Hot- 

 beds are generally heated by a bed of 



horse-dung, or other fermenting ma- 

 terial ; and biick-built pits, or houses 

 with glass roofs, are heated by fur- 

 naces and flues, or furnaces, boilers, 

 and pipes of hot water or steam. 

 Stable-dung and hot-water pipes are 

 the two best modes of heating pits and 

 glass-roofed houses. Heat when pro- 

 duced is retained by coverings which 

 admit the light, such as glass sashes, 

 or in some cases frames covered with 

 oil-paper, or with very thin canvas 

 or gauze. 



Heath. — See Eri'ca. 



Heath-mould is very frequently 

 confounded wi th peat-bog by amateur 

 gai-deners ; but the fact is they are 

 materially different. Black peat, 

 which consists of vegetable fibre, pre- 

 vented from decomposing by a super- 

 abundance of water, is unfit for the 

 growth of plants when in a pure state ; 

 but heath-mould, or i^eat mixed with 

 sand, is admirably adapted for the 

 growth ofall Australian and American 

 hair-rooted plants, as the mixture of 

 sand with the peat prevents its re- 

 tention of water, and it is only the 

 retention of water that prevents the 

 decomposition of the vegetable matter 

 it contains. — See Peat-bog. 



He'dera. — A7'aliacece.-Thel\j. 

 This well-known plant is what bota- 

 nists call a rooting climber ; that is 

 to say, its stems climb up and twine 

 themselves round trees, or any other 

 suitable object which present? a suffi- 

 ciently rough surface for their roots 

 to take hold of ; as, unless this is the 

 case, the Ivy, whenever it is rendered 

 heavy by rain or snow, falls down. 

 Whenever, therefore. Ivy is wanted 

 to cover smooth, newly j^lastered 

 walls, trellis work should be fixed 

 them, to which the Ivy should 



be nailed like any other plant. The 

 Ivy is remarkable for undergoing a 

 complete change in its leaves when it 

 flowers. The barren or creeping Ivy, 

 which trails along the ground, and j 



