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JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
May  5,  1904. 
The  Resting  of  Plants  nnder  Cnltiyation, 
(Coniiniicd  from  ^latje  360.) 
Cacti  and  Othep  Succulent  Plants. 
The  plant.s  under  this  lieading  are,  as  a  rule,  native  of  coun¬ 
tries  where  the  climate  is  severely  dry  for  a  certain  period  of  the 
year,  and  the  plants  are  modified  in  .structure  to  with, stand 
that  dry  season  by  the  storing  of  moisture  and  foo^l  substances 
in  the  kerns, and  leaves.  In  mo.st  of  tlie  Cacti  the  leaves  are 
absent,  or  they  are  reduced  to  spines  or  hairs.  This  is  the  case 
also  with  the  South  African  Euplun’bias  and  the  Stapelias.  The 
Aloes  and  a  good  many  of  the  Crassulac.eae  have  Avoolly  hairs  or 
a  waxy  substance  on  the  leaves.  All  these  characters  are  for 
the  puVpose  of  preventing  excessir^e  transpiration,  or  to  reduce 
it  to  a  minimum  amount,  during  the  time  Avhen  the  plants  are 
unable  to  take  up  moisture  through  the  roots,  owing  to  the 
dryness  of  the  .soil. 
"  When  coilsidering  the  I'esting  season  of  tliese,  we  must 
observe  the  difference  in  their  .structure.  For  instance,  the 
Aloes  and  the  Crassulacea'  both  have  fleshy  leaves,  but  the  Aloes 
generally  have  mucJi  more  substance,  and  will  therefore  Avith.stand 
a  longer  period  of  di'ought  than  some  of  the  thinner  leaved  Cras- 
sulaceae.  Noav,  the  majority  of  these  plants  Avill  stand  a  good 
quantity  of  water  during  the  bright  days  of  summer,  and,  in 
fact,  they  could  be  treated  as  ordinary  plants  and  benefit  by  it, 
as  the.se  are  the  conditions  ’  Avhich  most  nearly  approach  the 
growing  season  in  their  native  homes,  which  is  the  Avinter  or 
rainy  season. 
A  good  many  of  the  failures  Avith  these  plants  are  due  to  the 
excessive  application  of  Avater  during  our  AA’inter  months,  Avhen 
they  should  be  at  rest  ;  but  I  A'enture  to  .state  that  more  harm 
is  done  than  is  generally  supposed  by  Avithholding  the  Avater  for 
too  long  a  time,  so  that  the  plant  lo.ses  not  only  too  much  of  its 
substance  in  the  leaf  and  stem,  but  it  loses  the  majority  of  its 
roots  also.  This  is  more  apparent  in  young  plants,  Avhich, 
perhaps,  in  their  native  home  Avould  have  obtained  more  sub¬ 
stance  during  their  first  season’s  groAvth  than  they  do  Avith  us. 
When  at  rest  these  plants  Avill  Avithstand  a  fairly  loAv  tem¬ 
perature,  especially  if  they  are  carefully  looked  after  as  regards 
Avatering,  and  not  giA^en  too  much.  As  in  the  case  of  bulbs,  the 
higher  temperature  involves  the  necessity  of  more  frequent 
Avatering,  and  a  tendency  to  keep  the  plant  active  Avhen  it 
should  be  at  rest  is  the  result.  That  a  good  many  succulent 
plants  Avill  Avith.stand  colder  treatment  than  is  generally  sup¬ 
posed  may  be  seen  by  a  visit  to  the  Cambridge  Botanic  Garden, 
Avhere  Opuhtias  and  other  succulent  plants  rest  through  the 
winter  out  of  doors  Avith  piotection  from  rain  and  very  sharp 
frosts. 
Here,  again,  I  believe  success  is  dependent  a  good  deal  on 
the  preparation  of  the  plants  for  their  rest  by  a  gradual  Avith¬ 
holding  of  the  Avater  and  the  loAvering  of  the  temperature  ;  so 
that  by  the  time  Ave  may  expect  the  most  severe  Aveather  there 
is  no  very  young  and  tender  growth,  which  Avould  be  the  first  to 
suffer. 
Trees  and  Shrubs. 
The  majority  of  trees  and  shrubs  are  evergreen,  retaining 
their  foliage  throughout  the  year.  In  temperate  climates  tin 
evergreens  are  chiefly  cohifers,  and  the  other  Avoody  plants  are 
deciduous.  The  Avoody  plants  of  temperate  climates  form  Avintei 
buds,  or  resting  buds,  at  the  ends  of  the  branches  in  the 
autumn ;  often  even  Avhen  evergreen,  as  in  the  Rhododendron 
and  these  contain  all  or  part  of  the  next  year’s  groAvth  in  e 
more  or  less  developed  condition.  The  bud  is  exposed  to  evapo¬ 
ration,  cold,  Avet,  and  other  dangers,  but  is  protecteel  in  mosi 
cases  by  scales. 
These  are  sometimes  modified  leaves,  as  in  Acer  and  ^Fscidus 
sometimes  the  stipules  of  the  outer  leaves,  as  in  Magnolia  ;  some 
times  the  scales. are  hairy,  or  resinous,  so  that  they  form  an  effi 
cient  protection.  Many  buds  are  able  to  absorb  AA’ater  fron 
rain,  and  this  helps  them  to  recoA^er  that  Avhich  is  lost  by  evapo¬ 
ration  AAhen  the  roots  are  not  active. 
It  is  interesting  to  knoAv  that  these  Avinter  buds  of  trees  ant 
shrubs  liaA^e,  as  a  rule,  characteristic  .sizes,  shapes,  and  colours 
so  that  many  genera,  and  eA’en  species  can  be  distinguished  Iia 
the  characters  of  the.se  re.sting  buds. 
,  Oui  Biitish  plants,  as  I  have  stated  before,  obtain  their  resl 
l)y  the  loAvering  of  temperature,  and  usually  an  increased  supply 
of  AAatei  as  Avell ;  and  this  is  Avhat  AA'e  have  to  consider  AA'her 
selecting  foreign  trees  and  shrubs  for  our  gardens  as  permanenf 
plants  out-of-doors.  Those  from  other  temperate  regions  Ave 
can  usually  cultivate  Avith  success  Avithout  trouble  :  but  in  a  gooc 
coll^ection  there  are  many  AA’liich,  although  planted  in  the  mosf 
-suitable  situations,  against  walls  and  in  other  .sheltered  po.si- 
tions,  still  require  attention  to  help  them  to  survive  the  resting 
seasou.  by  protection  from  cold  winds,  frost,  and,  in  some  cases^ 
excessne  moisture.  These  are  usually  natives  of  a  warmei 
fm s  the  special  adaptations  .stated  above 
io!  cany  mg  them  through  a  cold  and  Avet  AA'inter. 
Thalictrum  anemonoides.  (See  page  386.) 
Here  the  question  arises.  Why  should  Ave  take  so  much 
trouble  Avith  these  foreign  plants,  Avhich  Avill  not  survive  our 
Avinters  Avith  a  moderate  amount  of  care  P  My  opinion  is  that 
Are  should  give  a  likely  plant  a  fair  trial  out-of-doors,  but  give 
it  up  if  Ave  find  it  is  not  likely  to  become  a  permanent  success ; 
bearing  in  mind  that  Avithout  these  trials  many  plants  Avhich  noAv 
grace  our  gardens  Avould  only  be  found  under  glass,  Avhere  they 
are  not  alAi  ays  seen  to  the  best  advantage. 
In  the  dry’  climates  of  subtropical  regions  many  deciduous 
trees  and  shrubs  are  found,  the  leaves  falling  at  the  beginning 
of  tlie  dry  .season.  Others,  which  are  not  deciduous,  possess 
leathery’  foliage,  Avhich,  like  the  succulent  plants,  have  their 
stomata  sunk,  and  in  many  ca.ses  have  the  leaf  surface  very 
much  reduced  to  prevent  exces.sive  transpiration  during  the  dry 
season.  But  under  cultivation,  especially  AAhere  they’  are 
groAA  n  in  pots,  Ave  do  not  find  it  advantageous  to  keep  them 
quite  dry  for  any  lengthened  period,  but  we  can  reduce  the 
supply  of  Avater  considerably,  Avhich,  Avith  a  loAvering  of  the 
temperature  during  the  Avinter,  Avill  give  them  a  sufficient  rest 
from  activity,  after  Avhich  they  AA'ill  groAv  Avith  increased  vigour 
Avheii  the  temperature  rises  in  spring,  and  an  increased  supply  of 
AA'ater  is  applied.  In  the  tropics  most  trees  and  shrubs  are 
evergreen,  although  they  have  a  tendency  to  form  neAv  leaves 
and  to  floAver  at  certain  periods.  Under  cultivation,  Ave  find  it 
l>est  to  keep  them  moderately’  dry  during  the  Avinter  months, 
AA  hen  the  sun  has  not  much  poAA'er  and  tlie  days  ai’e  short,  and 
consequently  the  temperature  is  considerably  loAver,  except  Aie 
use  a  great  deal  of  fire  heat,  and  this  Ave  find  is  of  no  adA’antage. 
Under  the.se  conditions  tropical  trees  and  shrubs  are  not  A’ery 
active,  and  it  servos  to  give  them  a  chance  of  keeping  back  the 
production  of  neAV  groAA’th  until  more  faA’ourable  conditions  of 
light  and  heat  can  be  obtained  during  the  lengthening  days  of 
spring.  There  are  .some,  hoAiever,  Avhich  Avill  not  Avithstand  a 
much  loAver  temperature  than  that  of  summer,  and  these  have 
to  lie  collected  to  the  Avarmest  part  of  the  house,  Avhere  they 
can  be  speciallv  cared  for.--E.  J.  All.ard,  Cambridge  Botanic 
Garden. 
(To  be  concluded.) 
