118 MISSOURI BOTANICAL GARDEN BULLETIN 
will not deal with this class of plants but will be devoted to 
those which can accomplish their whole development out of 
doors in and about St. Louis. 
The use of the garden hose is almost imperative to a good 
garden in St. Louis and floral effects can hardly be obtained 
without constant and regular watering. However, much 
work may be saved if the soil in the beds or shrubbery 
borders is kept constantly hoed or cultivated. The prim 
object of cultivation is not to eradicate weeds but to pul- 
verize the upper layer of soil and dry it out so that it will 
effectually prevent the evaporation of water from beneath. 
A mulch may also be obtained by spreading on the soil an 
such mineral as cut grass, manure, etc., but the soil mule 
obtained from constant hoeing is better for the plants and 
should be reéstablished after every heavy rain. When water 
is applied with the hose, the soil should be thoroughly 
saturated and then followed by careful cultivation. 
In general, flowering plants may be discussed by classi- 
fying them into four general groups, i. e., trees, shrubs, 
perennials, and annuals. The distinction between small trees 
and large shrubs is not very sharp, but a tree is usuall 
considered as possessing but one main trunk, while a shru 
may have several. Perennials, of course, are those herba- 
ceous plants whose roots, being hardy, produce new growths 
each year. Annuals are those sank octane plants growing 
and maturing from seed in one year. Some plants, ordi- 
narily: known as biennials because they mature the second ~ 
year from seed, will be classed as perennials. 
TREES 
Flower gardens depend upon trees for background effect, 
although during the flowering and fruiting period the trees 
are as interesting, if not as showy, as the flowers themselves. 
Among the really showy trees as regards flowering, the fol- 
lowing are a few which space permits mentioning. 
Aesculus Hippocastanum or Horse-chestnut.—This tree 
usually attains a height of 50 feet or more and a spread of 
about 30 feet. It is usually rectangular in outline and 
rounded at the top and has a good, though rather coarse, 
foliage of a deep green color. Naty to the same genus 
and of the same general habit is the hackers In early 
summer its large flower spikes of rather small flowers are 
very attractive, the varieties Wee in color from red to 
cream and white. As garden subjects, fault is often found 
with these trees because of the number of fruits with their 
husks which fall to the ground after the first frost, but this 
