280 
THE GARDENERS' CHRONICLE OF AMERICA 
lowing reason, which is quoted from Loudon's inter- 
esting account : 
"In 1770, a Parisian amateur named Petigny made a 
voyage to London in order to see the principal gar- 
dens; and among the number of those he visited was 
that of a commercial gardener who possessed five 
young plants of Ginkgo biloba, which was still rare in 
England and which the gardener pretended that he 
alone possessed. These five plants were raised from 
nuts that he had received from Japan, and he set a 
high price on them. However, after an abundant 
dejeuner and plenty of wine he sold to M. Petigny 
these young trees of ginkgo, all growing in the same 
pot, for 25 guineas, which the Parisian amateur paid 
immediately and then lost no time in taking away his 
valuable acquisition. Next morning, the effects of the 
wine being dissipated, the English gardener sought 
out his customer and offered him 25 guinea? for one 
plant of the five he had sold the day before. 
"This, however, was refused by M. Petigny, who 
carried the plants to France, and as each of them had 
cost him 120 francs, or forty crowns (quarante ecus), 
this was the origin of the name applied to this tree, 
and not because it was originally sold for 120 francs a 
plant. Almost all the ginkgo trees in France have 
been propagated from these five imported from Eng- 
land by M. Petigny. He gave one of them to the Jar- 
din des Plantes, which was kept for many years in a 
pot and preserved through the winter in the green- 
house, till 1792, when it was planted out by M. Andre 
Thouin, who gave the above relation in his lecture ; 
but as the situation was not at all favorable to it, this 
plant was not much above forty feet in height in 1834, 
and had not then flowered." 
CONSTRUCTING AND PLANTING A ROCK 
GARDEN. 
(Continued from page 270.) 
where the thick creeping root stock can attach itself 
to a flattish stone. It's a very striking plant. The 
leaves are shield-shaped standing a foot or so high and 
a foot across. The flowers white or pinkish stand 
well above the foliage. Deciduous. 
Saxifraga cordifolia and other varieties of the large 
leaved section are useful and ornamental and thrive in 
sun or shade. 
Saxifraga Aizoon valuable for its tufts of silvery- 
leaves has proved hardy but does not grow with vigor. 
Iris Cristata and Cristata alba, are easily grown 
plants and like a sunny position among small stones. 
Iris Arenaria is more curious than beautiful and a 
vigorous grower. 
Iris pumila and Iris germanica are worth some place 
in a rockery as they are not at all difficult to grow in 
dry and sunny situations. 
The perennial Candytuft Iberis sempervirens is in- 
dispensable for rockwork and thrives in dry or wet 
situations. Partial shade does not hurt them. They 
brown up in spring sun. Daphne Cneorum, Euphorbia 
polychroma, and the Solomon's Seal, Polygonatum 
multiflorum are all attractive and thrive in any situa- 
tion not too heavily shaded. 
The Epimediums will grow and bloom freely in 
places where the sunlight seldom or never strikes 
them. They are the best plants I know of for hold- 
ing the soil of steep banks in place and for planting 
in vertical fissures. The white flowered and yellow 
kinds are the showiest. 
Vancouveria hexandra is similar in appearance to 
Epimedium and thrives under the same conditions. 
1 he Bugle flowers, or Ajuga, are good plants for 
shady banks or spots where the soil is shallow or 
stony. 
Acaena microphylla, and A. sarmentosa are pretty 
plants for ground cover, but have not proved reliably 
hardy. 
Saponaria ocy-moides and Saponaria versicolor are 
both pretty flowered trailing plants and very useful ; 
they will flower well in slight shade. They have long 
fleshy roots and require deeper soil than the Phlox 
subulata. 
The Climbing Hydrangea, English Ivy and Euony- 
mus redicans are useful for covering stones or the 
faces of natural ledges. The Ivy must be protected 
from the late winter or early spring sun or it will 
burn. Burlap is the best material to use for that pur- 
pose. 
The Polemonium and Dodecatheon can be relied 
on to give pleasure in any half-shaded spot. 
The Gentiana, Linum, Thymus, Achillea, Dianthus, 
Silene, Cerastium, Stokesia, Gypsophila and Veronica 
are all sun loving plants and will not thrive immedi- 
ately beneath trees of any kind. The shade from de- 
ciduous trees is not harmful unless very dense and of 
long duration. 
Gentiana acaulis is a beautiful flower of good size 
and color, easy to handle. The plants should be set 
among half buried stone chips. 
Gentiana verna is pretty but difficult to establish. 
Silene alpestris and Silene maritima, Acantholini' >n 
glumaceum, Androsace Chumbyi, Cerastiums tomen- 
tosum and biebersteinii, Heuchera, and Stellaria Ho- 
lostea all these have done well although in the shade 
part of the time. 
In closing I wish to say that Dictamnus fraximella 
albus never shows to better advantage than when 
growing between tall rocks. 
Hemrocallis is another plant that can be grown set 
between large rocks or stones. 
The Ranunculus are satisfactory plants for rockeries. 
Ranunculus amplexicaulis, R. aconitifolius flore-pleno, 
and R. acris flore-pleno are the best we have tried. 
The number of plants to be had for planting rock 
gardens far exceeds the list I have named and only 
by experimenting is it possible to prove their value 
for use in this country. 
Extracts from paper read before the Boston Garden- 
ers' and Florists' Club. 
USEFUL BIENNIALS 
T I 
'HE term "biennial," though decidedly misleading, 
inasmuch as it is made to include many plants 
which are really perennial, is a very convenient one, 
and to gardeners it usually means a plant sown one 
year that will bloom the next, and then die. Biennials 
certainly include some of the most beautiful and most 
indispensable garden flowers, and when we see wall- 
flowers, Canterbury bells, sweet williams and evening 
primroses, we are made to think of our childhood's 
days. 
The uses of biennials are very numerous and varied. 
All gardeners are familiar with their more obvious 
uses, such as for spring bedding, but of late it has 
become the fashion to place biennials in the mixed 
border along with annuals, instead of keeping the bor- 
der for perennials only\ Biennials are also useful for 
placing on a sloping piece of rockwork to provide 
bright color in the early summer; for brightening up 
the boundaries of shrubberies, and for other purposes. 
The blooms of sweet williams and Canterbury bells. 
