COVERING OF GLAZED AND OTHEE IIORTICULTUKAL STEUCTURES. 
zE^ 
one plant at a time. By this plan, I have always the same numher of shoots in fi-ee growth, and the 
. plants very little taller at the end of tlu'ee months than they were in the fii'st mouth. 
Apolla. 
Beauty of Stow, 
Chauvicrii. 
Conite de Paris. 
Defiance. 
Duchesse de Gazes. 
Eclipse. 
General Brea. 
Henriette. 
John Salter. 
Madame La(,'on. 
Minerva. 
Mount iEtna. 
Mountain of Snow. 
Princess Alice. 
Psyche. 
SELECT VEIIBENAS. 
Queen of the French. 
Queen of Sunnner. 
Saint Mai'gai'ot's. 
Tricolor. 
Comtesse de Mubiaon. 
Aiiadne. 
General Lamoriciere. 
Gracieuse. 
Heloise. 
Madame Eevenclion. 
Baucis. 
Bicolor Grandiflora. 
General Vandecour. 
La Coquette. 
There are a few varieties better adapted by their natural habit for having- the pips thinned out, and 
this is best done with a paii' of sharp-pointed scissors, the thinning operation being- performed a few 
days prior to the day of exhibition, so that the remaining pips may have time to fill up well. These 
plants will, by the end of July or August, have exhausted the soil, or nearly so, and will no longer 
fiu-nish good trusses ; to remedy tliis, I strOie a fi-esh stock in June, for the September exhibitions, 
treating them in every respect as before. 
The Verbena should be carefully watched when under glass : the green fly is a great enemy to it) 
as also is mildew ; in either case prevention is better than cm-e, and an early application of the following' 
taken in time, will often be the means of sa^dng the plants, when perhaps delays may prove dangerous. 
The most simple method of destropng the aphis on the plants in pits, or frames, is to place a few 
hot cinders at the bottom of a seven-inch pot, place tobacco enough on the cinders for the size of the 
pit, setting the pot at the fi-ont part of the pit ; shut it up close and cover it with wet mats. The 
plants must have been in a very bad state indeed, if this does not relieve them. 
For mildew the following is a remedy : — On its first approach, make a weak solution of tm-pentine, 
with which water them over-head, through a fine rose watering-pot ; this should always be done in 
the evening, and will generally prove effectual. 
The soil I prefer is, equal parts of peat, loam, leaf-mould, and ehai-coal ; and of guano a small 
portion — the guano well pounded, the others as rough as possible. 
By following- the above plan, and selecting plants from the List above, the Verbena may be 
exhibited in such a manner as cannot fail to make it a general favourite at the summer and autumn 
exhibitions. 
COVERING IN ITS GENERAL APPLICATION TO GLAZED AND OTHER 
HORTICULTURAL STRUCTURES. 
By Mr. GEORGE SMITH, Brookl-Utos Nursery, Blackheath. 
M MORE appropriate season than the present cannot well be chosen for the consideration of this 
iV2\ important subject, the more especially as gardeners and amateui-s, frequently at the eleventh horn', 
have to apply materials of various descriptions, some of wluch are not adapted to the pm-pose, and in 
some cases turn out totally ineffective. It is, therefore, desii-able to be prepared to determine which 
are the proper materials for the purpose, and what is the most effective method of applying them. 
Dr. WeUs, in his vei-y admii-able essaj's on the formation of dew and hoai'-frost, found that a 
cambric handkerchief, suspended a tew inches above a thermometer placed upon a grass-plot, kept it, 
on a stiU night, several degrees higher than another thermometer which was fvdly exposed ; and we 
all know very well that the intervention of a cloud on a frosty night -svill prevent one place from being 
affected by fr-ost, while another garden, not a very great distance off, but not so protected, mil suffer 
severely. And why is this ? Because the handkerchief and the cloud alilie prevented the radiation of 
heat into space, and therefore, being coirhned about the plants, prevented their being injm-ed. Finding, 
then, that so slight a fabric as a thin handkerchief, or a fibny cloud, makes so great a difference in the 
open air, what an important advantage it would be to use a proper covering for oui- forcing-houses in 
severe weather. As to the best material to use for the protection of oiu- houses, and frames, there is great 
diversity of opinion. Mats have been used for a great number of years, and are still very much 
esteemed by some cultivators, though, for my o-wn part, I have always been opposed to their use. 
They are extremely expensive, and after a few months' use are by no means effective. Theii- beinj 
non-conductors of heat certainly recommend them, but they are by no means dm-able, neither are they 
effective in severe frosts, miless used in larger quantities than most gai'deners can command. The late 
