Salix purpurea 'Nana'

Dwarf Purpleosier Willow

Arching

Long stems rise from the base, then bend outward and down at the tips, like a fountain.

e.g., Forsythia

Climbing

Grows up a wall, trellis or other plant, holding on with tendrils, twining stems or aerial roots.

e.g., Ivy, Clematis

Clump-forming

A tight, slowly widening clump of stems or leaves from one crown, without runners.

e.g., Daylily

Columnar

More narrow than wide. Usually with a height to width ration of 5-to-1 or greater.

e.g., Lombardy Poplar

Conical

Cone shaped

e.g., Spruce

Fastigiate

Having an upright branching habit. Sometimes the upward sloping branches can look like they’re part of a single column.

e.g., Irish Yew

Pendulous / Weeping

Branches and branchlets hang downward, often to the ground, like a curtain.

e.g., Weeping Willow

Prostrate / Creeping / Mat-Forming

Grows flat along the ground, spreading outward rather than up; stems often root where they touch soil, forming a mat.

e.g., Creeping Juniper

Spreading / Branched

Strong limbs reach out horizontally, making a crown as wide as the plant is tall, or wider.

e.g., Oak

Stoloniferous

Spreading by means of stolons (horizontal stems) and shoots that grow along or under the ground at the ends of which new plants can sprout.

e.g., Strawberry, Bugleweed

Suckering / Colonizing

Sends up new shoots (suckers) from the roots or base, spreading into a thicket or colony.

e.g., Sumac

Tiered

Branches grow in distinct horizontal layers, one above another, with open space between.

e.g., Pagoda Dogwood

Trailing

Long, loose stems drape downward or sprawl without rooting at the nodes.

e.g., Periwinkle (Vinca)

Upright

Main branches angle upward at about 30–45°, making a crown taller than wide but not narrow.

e.g., Japanese Zelkova

Other

A form none of the above describes, such as irregular or sculptural.