THE OLD GARDENS OF PENNSYLVANIA 
IX. —ARBORETUM AT ALDIE NEAR 
DOYLESTOWN, PENNSYLVANIA 
JOHN W. HARSHBERGER 
Professor of Botany, University of Pennsylvania 
jUCKS County, Pennsylvania, north of Philadelphia, 
is one of the rich agricultural counties of the state, 
noted for its gardens and other horticultural estab- 
lishments. It boasts a number of places of great scenic 
beauty; for example: Haycock Mountain; the shores of the 
Tohickon Creek; and the Delaware Palisades, or Nockamixon 
Rocks, as perhaps they are better known; also the celebrated 
Ringing Rocks frequently visited by the geologist and nature 
lover. 
Among the estates in the beautiful country adjacent to the 
city, none is finer than Aldie, the home of Mr. W. R. Mercer, 
one mile north of Doylestown, the county seat. Here are 
thirty acres of rich land devoted almost exclusively to the 
arboretum and flower gardens planned by the present owner’s 
father, William Robert Mercer, who was born in 1827 and died 
in 1917 at the ripe age of nearly ninety-one. Although part 
of the area was in a garden, when Mr. Mercer senior began to 
plant it, yet the present plantation may be said to date from 
1870, when the large house was built. The arboretum and 
formal gardens were also started in 1870, so that Aldie is the 
youngest collection of trees described in this series of articles; 
although, when we stop to think, full fifty years have elapsed 
since the first planting was begun. Some of the trees, there- 
The figures in the 
map indicate the 
locations of the 
gardens and their 
sequence in the 
series 
fore, have reached a considerable size, and begin to show the 
characteristics of maturity. Aldie was named for the ancestral 
home of the Mercer family in Scotland; there is also another 
Aldie in Virginia established by the Mercers. 
The main road from the entrance nearest Doylestown leads 
in a curving direction to the old house built in 1870 with its 
terraced porches and planted grounds immediately in front. A 
clear brook winds its way through the southern part of the 
arboretum and is crossed by two roads built over arched, stone 
culverts. The trees are grouped on both sides of the main 
driveway and the planting has been done judiciously, so that 
there are open stretches of lawn with the tree groups arranged 
to form extensive vistas after the English style of landscape art; 
AN AID TO THE GENTLE ART OF LOITERING 
A cloister in the Italian manner at Aldie which evidences the skill 
and artistic appreciation of its owner as a manufacturer of cement 
326 
