HEATH-HOUSE. 



703 



until the new heads are again formed. Such is 

 the treatment, also, for newly-imported plants 

 which may be in a sickly state. 



The Continental gardeners attach great im- 

 portance to pruning, which they perform in 

 rather a wholesale manner, using the hedge- 

 shears, with which they clip the heads as close 

 and symmetrical as if they were more intent on 

 the production of a perfect vegetable sphere than 

 on balancing the top to the capabilities of the 

 roots. Thinning the branches is less regarded 

 than maintaining symmetry of form, although 

 some of the best gardeners give their trees a 

 sort of winter-pruning (talk), and also a sum- 

 mer-dressing (ebouryeonnemexf). The heads of 

 their trees become, notwithstanding these prun- 

 ings, in course of a few yeai'S both too large and 

 too much crowded with branches to be supported 

 by the roots, and hence every sixth or eighth 

 year a general reduction of the head takes place, 

 which would be avoided were an annual pruning 

 practised. At the general pruning, every shoot 

 on the tree is cut back to within an inch or two 

 of the old wood, leaving them bare and leafless 

 stumps, which require two or three, and often 

 more, years to recover. Where the roots are in 

 a good condition, these trees break into young 

 wood, often with surprising vigour, and after- 

 wards become as large, and are trained as globose 

 as before. The irregular form given the trees 

 in Britain is not only more agreeable to the sight, 

 but is more conducive to their health ; they are 

 thinned and trained like any other standard tree, 

 keeping the branches moderately thin, shorten- 

 ing such shoots as greatly outgrow the others. 

 As the blossoms, for the most part, are produced 

 in form of terminating peduncles on the wood 

 of the current year, it follows that in pruning 

 encouragement should be given to the produc- 

 tion of young wood in every part of the tree, 

 cutting out all naked wood, and shortening 

 strong shoots where wood is wanted. 



Those who have not a regular orangery may 

 place them in the camellia-house, where they 

 will associate well with the tender rhododen- 

 drons, Chinese azaleas, and similar plants (mde 

 Camellia-house). Oranges may also be kept in 

 the greenhouse or conservatory, but in either 

 case the temperature is too low for the perfect 

 ripening of their fruit. The following are the 

 most esteemed varieties of the common orange : 

 th e China, Blood-red,Sweet-skinned, St Michael's, 

 Mandarin, Fingered, Tiny - fruited, and Pear- 

 shaped ; and of these the Mandarin and St 

 Michael's are the most proper for cultivating 

 for their fruit. 



Insects and diseases. — That general enemy to 

 all plants under glass, the red spider, fig. 22, 

 and the plant aphides, both attack the Citrus 

 tribe. Copious syringing destroys the former, 

 whose appearance is a sufficient indication that 

 the atmosphere has been kept too dry. Tobacco 

 fumigation is fatal to the latter. The orange 

 scale insect, Coccus hesperidum Linn., is a worse 

 enemy to subdue than either of the others. In 

 appearance it resembles an elliptical nut-brown 

 shield, attaching itself to the branches and 1 eaves, 

 particularly when the trees are kept rather warm. 

 The trees should be carefully washed with soap 



and water, applied by a rather hard brush during 

 autumn, when few young insects are found : the 

 old ones, being displaced, cannot creep up again; 

 but lest they produce their young while on the 

 floor, or the surface of the soil in the pots, it is 

 well to spread a cloth under the trees during 

 the operation of washing, into which the coccus 

 will fall, and hence be removed out of the 

 house. 



§ 5. — HEATH-HOUSE. 



No individual genus of plants forms so com- 

 plete a whole, or is so eminently adapted for 

 occupying an entire house, as the Ericas. The 

 genus is extensive, embracing upwards of 560 

 species, besides numerous hybrids, originated 

 artificially in various parts of Europe, but prin- 

 cipally in Britain. They are of easy culture, of 

 vast variety, and flowering at all seasons of the 

 year. The whole of this vast assemblage are 

 natives of the Table Mountain at the Cape of 

 Good Hope, with the exception of five which 

 are indigenous to Britain, three to Portugal, one 

 to France, one to Northern India, one to Sicily, 

 one to Spain, and four to the rest of Europe. 

 They all occupy elevated ranges, enjoying a 

 pure air, refreshed by copious dews, and ex- 

 posed for long periods to a dry arid atmosphere. 

 They are all moderately hardy, with the excep- 

 tions we have given, but not so much so as to 

 withstand the severity of our ordinary winters 

 without a glass protection. Enjoying, as we 

 have said, a pure air naturally, they do not 

 prosper in or near towns, and soon perish when 

 placed in the dry close atmosphere of rooms. 

 They are impatient of fire heat, and are found 

 to thrive best in a light airy house, into which 

 artificial heat is rarely admitted. 



"We have in vol. i., p. 402, spoken of the 

 merits of a complete heath-house, and given 

 examples, iiide figs. 552, 554, and 555. We 

 have only further to remark that such a struc- 

 ture should either be span-roofed, as there 

 exemplified, or curvilinear, and that all lean-to 

 houses are objectionable for the purpose. The 

 roof should also be low that the plants may be 

 placed near to the glass ; for although many of 

 them may be grown to a large size and con- 

 siderable height, the majority do not, nor is 

 it for general satisfaction that they be so. 

 From 1 to 3 feet is a very proper height for any 

 heath. Abundant ventilation is of the utmost 

 importance to their welfare ; and this should be 

 so arranged that the air may enter close to or 

 near the floor, particularly during winter, and 

 not be allowed to blow directly upon them, un- 

 less during summer. The stages or platforms 

 should be of open cast-iron ornamental grating, 

 both for durability and elegance, and also that 

 the air may find its way to their roots, and that 

 superfluous or spilt water may find a ready 

 means of escape. When slate or stone shelving 

 is used (which are the next best materials), the 

 pots should have the bottoms well perforated 

 with holes, and made to stand clear of the table 

 from half an inch to an inch and a half, in pro- 

 portion to their size. When pots of the ordi- 

 nary make are used, and set upon a close plat- 



