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ROTATION OF CROPS. 360 
ROT-HEAP. 
_—_— 
—A very handsome shrub, with 
pinnate leaves, and long drooping 
racemes of rose-coloured flowers. 
It will grow in any soil, but it should 
be placed in a sheltered situation, 
on account of the brittleness of its 
branches, and their liability to be 
broken off by high winds.—See 
Ropsi'nia. 
Rose Bay.—See Ruopops/NDRON 
and Ne‘rium. 
Rose Campion.—Agrostémma.— 
The very pretty flowers known by 
this English name are included by 
many botanists in the genus Lych- 
nis. Many of the kinds are an- 
nuals ; but the common Rose Cam- 
pion, A. coronaria, is a perennial. 
Rosemary.—See Rosmari'nus. 
Rose or Hraven.—Agrostemma 
or Ly'chnis Celi Rosa, an orna- 
mental annual from the Levant, 
quite hardy in British gardens. 
Rose or Jericso.—Anastiatica 
hierochuntina.—A cruciferous an- 
nual from the Levant, of no beauty, 
but curious from the manner in 
which its branches curl round the 
seeds when they are ripe. The end 
of the shoot containing the seeds 
thus protected, falls off, and is 
blown by the wind from place to 
place, without discharging the seeds, 
so long as it is dry; but as soon as 
the ball reaches a moist place, where 
the seeds can germinate, the pro- 
tecting branches relax, and the seed 
drops out. 
Rose or Suaron.—NSee Hini'scus. 
Rose-roor.—See Ruopr‘oa. 
Rosmarinus. — Labidte. — The 
Rosemary, R. officinalis, is a well- 
known shrub, which will thrive in 
any sheltered situation, but which 
is liable to be injured by frost in se- 
vere winters. It will grow in any 
common garden-soil; and it is 
propagated by cuttings, planted in 
spring. 
Rotation or Crops.—It has been 
found by a series of experiments 
that the same kind of annual plant 
i." 
should never be grown for more 
than two years in succession in the 
same ground, without manuring or 
renewing the soil; as plants either 
throw out a quantity of excremen- 
titious matter, which they will not 
reimbibe, or exhaust the soil of all 
those properties which are nourish- 
ing for them. The ground, how- 
ever, which thus becomes unfit for 
one kind of plant, is found to be 
suitable for another kind quite dif- 
ferent ; and the making these plants 
succeed each other in a proper man- 
ner is called the rotation of crops. 
Perennial plants, and trees and 
shrubs, are not so liable to injury 
from their poisoning the soil, as they 
elongate their roots every year, so 
as to have their spongioles always 
in fresh soil ; but some shrubs, such 
as Roses, which never have long 
roots, should either be transplanted 
every third or fourth year, or have 
manure laid on the surface of the 
soil, to supply them with fresh food. 
tOT-HEAP is a heap composed of 
sand, and such fruit as haws, holly- 
berries, ashkeys, hornbeam-nuts, 
and similar seed-vessels, which is 
turned over several times in the 
course of the winter, to promote 
the decomposition of the exterior 
covering of the seed. The object 
is to save room in the nursery, be- 
cause these seeds, and others, if _ 
sown before the flesh or exterior 
covering is rotted off, will lie dor- 
mant in the soil for a year; where- 
as, by rotting it off and sowing the 
seeds in the spring of the second 
year after which they are gathered, 
they come up the following May or 
June. The rot-heap is kept in what 
is called the rotting-ground, which 
may be in any open situation fully 
exposed to the weather. ‘The heaps 
may be one or two feet in thickness, 
and of any convenient width, the — 
object being to produce decay with- 
out inducing such an active fer- 
mentation as would generate suffi- 
" ¥ 
