The summer linden has a broad, ovoid to round crown and a rounded top. The trunk is heavy and irregular, light grey and later grooved. The heavy lateral branches are usually found low on the trunk. A lot of root suckers usually grow from the lower trunk. After one year, twigs are hairy and reddish brown, and become bare in the winter. The leaves of T. platyphyllos emerge a fortnight sooner than those of T. cordata and are also larger. The leaves are heart-shaped with a tapered top and a slanted heart-shaped base. The edge is sharply serrated. The upper side of the leaf is dark green while the underside is light green with soft hair. The aromatic flowers hang in umbels of 3 to 5 together; the bract is clearly stemmed and approx. 5 cm long. T. platyphyllos is not very prone to aphids. A very strong tree.