785 
December 19, 1908. THE GARDENING WORLD. 
for planting in clumps or masses on the top 
ol walls. Very suitable ones are Semper- 
vivum tectorum, S. calcareum, S. montanum, 
S. globiferum (known as Hen and Chickens), 
S. arenarium, S. arachnoideum (Cobweb 
Houseleek), S. Laggeri, a little larger than 
the last, and others if you can get them. If 
you have a portion of wall that is shaded 
from the midday and afternoon sun, and 
keeps fairly moist, you can grow Ramondia 
pyrenaica, R. p. alba and R. serbica Nath¬ 
alie, which are very choice rock plants in¬ 
deed. 
3469. Plants and Ferns for Rockery. 
Would you be pleased to give me the 
names of about a dozen or eighteen rockery 
plants that would be hardy in this district, 
as I would like to try my hand at this style 
of gardening? I can get plenty of stones to 
build it with. Ferns grow well, and you 
might name some of the small growing kinds 
to plant among the stones. (R. McK., 
Banffslhire.) 
The rock plants that would grow with you 
are very numerous, because many of them 
come from high elevations and like to be 
kept cool and resting in winter. We have 
selected the number you ask, together with a 
dozen of the smaller types of British Ferns 
that should succeed with you. The flower¬ 
ing plants are Aubrietia Dr. Mules, A. 
Leichtlinii, Lithospermum prostratum, 
Iberis sempervirens, I. correaefolia, Ane¬ 
mone nemorosa fl. pi.. Campanula pumila, 
C.p. alba, C. portenschlagiana, C. turbinata 
pelviformis, Veronica Teucrium dubia, Poly¬ 
gonum vaccinifolium, Saxifraga caespitosa, 
S. decipiens, S. Rhei Guildford Seedling, S. 
Wallacei, S. Aizocn, and S. Hostii. The 
Ferns are Aspleniunj Adiantum-nigrum, A. 
fontanum, A. marinum, A. Triohomanes, 
Blechnum Spicant/Cryptogamme (Allosorus) 
crispa (Mountain Parsley), Cystopteris fra- 
gilds, C. regia, Scolopendrium vulgare, S.v. 
crispum. Polypodium vulgare cambricum 
(Welsh Polypody), and P.v. semilacerum. 
Of the above Ferns, A. marinum would be 
the most difficult, but in a moist situation be¬ 
tween stones we think you could manage it. 
3470. Hardy Cyclamens. 
Would you please name some of the har¬ 
diest Cyclamens I could grow, the best or 
most suitable soil for them, and the best time 
to plant them. I have had a try with the 
greenhouse binds, hut they did not flower 
very freely in a cool greenhouse. (Inex¬ 
perienced, Hants.) 
The hardiest Cyclamens are C. neapol-ita- 
num and its varieties C. 'Gaum, C. ibericum, 
and the hybrids between the two latter, and 
C. europaeum. All of the above can be 
grown cut of docxrs, and you should be suc¬ 
cessful with all ol them, with the exception, 
perhaps, of C. europaeum, which is a little 
more difficult. C. neapolitanum blooms dur¬ 
ing September and October before the leaves 
commence to grow. C. Coum and C. iberi¬ 
cum bloom in early spring, and C. euro¬ 
paeum about the beginning of summer. 
Spring would be the best time to plant them 
now—say, about the end of March or begin¬ 
ning of April. Select a half-shaded situa- 
' tion, where they may get sun only in the 
early part of the day. If your soil is heavy 
about 1 ft. of it should be taken out, and 
after putting in some drainage in tihe bottom 
you should make up a compost consisting of 
two parts of loam or old potting bench soil, 
one part of leaf-mould, and half part of 
sand. The leaf-mould will serve to retain 
the moisture in summer and forms agreeable 
rooting material for the Cyclamens. An 
annual top dressing of this may be given 
every year about the end of March, using 
equal parts of soil and leaf-mould. Those 
that retain their leaves into warm weather 
should have a good watering now and again. 
3471. Sweet Peas for Exhibition. 
Will you kindly, in your next issue, favour 
me with your opinion re the following Sweet 
Peas for competition :—Paradise Carmine, 
Evelyn Hemus, Helen Lewis, Mrs. C. Fos¬ 
ter, Countess Spencer, John Ingman, Bur¬ 
pee’s King Edward Spencer, Burpee’s Apple 
IjSlossom, Morse’s Ramona Spencer Blush, 
Bath’s Princess Catherine Spencer White, 
Josephine Banard Rose, and Mrs. Hardcastle 
Sykes. Which is the best for competition, 
Mrs. Hardcastle Sykes or Messrs. E. V. 
King's Blush Spencer? Have you seen any 
of these American varieties in hlcom, or do 
you think I could improve my list by omit¬ 
ting them and substituting English ones for 
them? I do not desire to grow any two va¬ 
rieties which are alike. (Arthur Burton, 
Pembrokeshire. ) 
Paradise Carmine is about the same as 
John Ingman. Either of them might be 
shown, but not both in the same stand. 
Evelyn Hemus is a dainty picotee-edged 
variety on a creamy ground, and is very dis¬ 
tinct. * Helen Lewis is a grand variety, and 
is classed amongst the orange shades. Mrs. 
C. Foster is a lavender and good when it 
comes true, but is not yet fixed. Countess 
Spencer is a splendid pink when it comes 
true, hut is liable to sport into other varie¬ 
ties. John Ingman is a rich rose variety 
and a very valuable one to grow if you get 
seeds from a good source. Burpee’s King 
Edward Spencer is a grand variety with 
crimson flowers, but liable to burn in the 
eastern counties. It should do well with 
you, however. The other varieties you men : 
tion in your list down to Josephine Banard 
cannot be described with much certainty, as 
it is too soon to determine their merits for 
different parts of this country. A good plan 
would be to stick to those that have been 
well tried before embarking upon the newer 
kinds, though we do not advise you to give 
up growing a few novelties every year. Mrs. 
Hardcastle Sykes is a blush-pink, fixed and 
very reliable. We should prefer it to the 
other variety you name, as it is very little 
known, and as far as we can see is not listed 
in the raiser’s catalogue. Me have seen a 
good number of the American varieties, but 
they do net offer anything superior to what 
we have, with the exception, perhaps, of 
King Edward Spencer, which is a good 
thing. Of the list you mention, you should 
certainly get Evelyn Hemus, Helen Lewis, 
Countess Spencer, John Ingman, King Ed¬ 
ward Spencer, and Mrs. Hardcastle Sykes. 
A letter concerning Sweet Peas will appear 
when space can be found for it, and that 
will give you some information that will 
help you in deciding which to get of the 
varieties under ddscussicn. 
LAWNS. 
347 2. Rolling a Lawn. 
Under what conditions is i.t advisable to 
roll a lawn during the summer months—ex¬ 
clusively or chiefly after rain, or during 
even dry weather? In autumn and winter 
should iit be rolled as often as possible? 
(Enquirer, Dines.) 
Gardeners are sometimes obliged to roll 
their lawns when they can, sometimes when 
net in the best condition. For preference we 
should select a time long enough after it had 
ceased raining for the grass to get fairly dry 
to prevent it gathering up on the roller, or 
the latter from picking up soil where there 
happens to be bare spots. The theory is that 
it is not advisable to roll a lawn when it is 
so wet as to be muddy. The ground should, 
of course, be moist, as it can then be pressed 
down more easily and regularly with the 
roller than if it were dry and hard. Pre¬ 
ferably, the grass should be dry, but the 
soil moist when you are about to roll it. 
This would be after the rain has partly 
dried up. In dry weather if there has been 
no rain for some time the roller would make 
no real impression upon the soil. It would 
be necessary to give it a good watering and 
then roll it after the water had sunk into the 
soil, leaving the grass fairly dry. You can 
roll it as often as you like during autumn 
and winter, as this will tend to make it 
solid and agreeable to walk upon. Some 
people object to having to do the work too 
often, but we should consider one rolling a 
week quite sufficient for any lawn, unless 
there was an unusual amount of traffic upon 
it. 
TREES AND SHRUBS. 
34.73. Cytisus praecox. 
To what height does Cytisus praecox grow 
and what distance apart would you plant 
them? (Enquirer, Lines.) 
It depends very much upon the character 
of the soil as to the actual height this plant 
will grow. It is considered to be a hybrid 
between 'Cytisus purgans and C. albus. It 
is, therefore, correctly named Cytisus prae¬ 
cox. M~hen planted on rockeries and simi¬ 
larly dry positions, it flowers freely and 
may not grow more than 2^ ft. to 3 ft. high 
during the course of years. In moister and 
deep soil it may grow 4 ft. or over. If you 
intend to plant a clump of it and the soil 
is good, you cpuld let them have 2^ ft. to 
3 ft. between every two. In the course of 
some years they will fill up this space, and 
in the meantime you may plant bulbs or 
some other low-growing subjects between 
them until the Cytisus had time to spread 
and occupy the space. If you do not want 
them to become crowded, or unequal in 
growth, you can shorten back branches where 
crowding happens to be or cut out old 
branches, leaving young ones to take their 
place. If you regulate them like this every 
spring just after flowering they will occupy 
the same space for many years. 
CHRYSANTHEMUMS. 
3474. Mildew on Chrysanthemums. 
The Chrysanthemums in my cold green¬ 
house are getting all their leaves like the 
enclosed. Is it mildew? If so, what is 
best to be done and are other kinds of plants 
in danger? (N. E. C., Kent.) 
Your Chrysanthemums must be very badly 
affected with mildew if they are all like the 
leaves you sent us. If the plants have 
finished flowering the old stems should be 
cut down and taken away and that will give 
you more space and light for the benefit of 
the young shoots coming up from the base. 
If the latter are also attacked with mildew 
you should dust them with flowers of sulphur 
at once. If the leaves are slightly sprayed 
before dusting them it will make the sulphur 
adhere better. When fresh leaves are made 
they may also get attacked, but you should 
dust them at once. The secret of success is 
to attack the mildew on its very earliest ap¬ 
pearance. At the same time you must venti¬ 
late regularly, so as to keep the atmosphere 
'of the house cool and dry. Indeed, if you 
have a cold frame that can be ventilated 
every day the Chrysanthemums would be 
less likely to get mildewed there than in a 
greenhouse amongst other subjects. Different 
kinds of plants may get their own particular 
forms of mildew. Chrysanthemums might 
cause certain other closely allied plants to 
get mildew, but the} 7 would not affect more 
distantly-related plants. In any case, you 
should get rid of the mildew. 
VEGETABLES. 
3475. Perennial Spinach. 
Can you tell me anything about peiennial 
Spinach, which I should like to try,-as I 
have had bad luck with winter Spinach sown 
at the beginning of September? Would New 
