Tape Grass

Vallisneria americana

· aquatic · introduced

Last updated March 8, 2026

Data Coverage 2 of 6 dimensions

Site Data

Threats

Cultivars

Phenology

GDD Thresholds

Puget Sound

Quick Facts

Height

1 ft

Growth Rate

Fast

Light

Full Sun

Soil

Wet Tolerant

Water

High

Hardiness

Zone Zones 4a–9b

Bloom Time

Jul 1-Jul 31

Stage	Typical Window	What to Look For
Bud break BBCH 07	May 15-Jun 15	Buds swelling and beginning to open; first green tissue visible
Leaf emergence BBCH 11	Jun 1-Jul 1	First leaves fully unfurled on new growth
Bloom start BBCH 61	Jul 1-Jul 31	First open flowers visible
Bloom end / petal fall BBCH 69	Jul 15-Aug 15	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Jun 1-Aug 31	Fruit or seed structures forming; fruit color: green
Leaf drop BBCH 93	Oct 15-Nov 30	Leaves yellowing and dropping; no significant fall color display
Dormancy BBCH 97	Nov 15-Feb 28	Leafless; no active growth; dormant buds set