Blunt Spikerush (Obtusa)

The Blunt Spikerush (Obtusa) is generally described as a perennial graminoid. This is native to the U.S. (United States) has its most active growth period in the spring . The greatest bloom is usually observed in the summer, with fruit and seed production starting in the spring and continuing until fall. Leaves are not retained year to year. The Blunt Spikerush (Obtusa) has a short life span relative to most other plant species and a moderate growth rate. At maturity, the typical Blunt Spikerush (Obtusa) will reach up to 1.6 foot high, with a maximum height at 20 years of 0 inches.

The Blunt Spikerush (Obtusa) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, seed, sprigs. It has a moderate ability to spread through seed production and the seedlings have medium vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below 37°F. has low tolerance to drought and restricted water conditions.

Plant Basics
Growth Rate Moderate
General Type Graminoid
Growth Period Spring
Growth Duration Annual, Perennial
Lifespan Short
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Summer
Displays Fall Colors No
Shape/Growth Form Rhizomatous
Drought Tolerance Low
Shade Tolerance Intolerant
Height When Mature 1.6
Vegetative Spread Moderate
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Spring Fall
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Seed, Sprigs
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature 37
Soil Depth for Roots 10
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate None
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4.1–8.7 pH
Precipitation Range 18–18 inches/yr
Planting Density 2700–4800 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 10
Minimum Frost-Free Days 120 day(s)
Salinity Tolerance None
CaCO3 Tolerance Medium
Sustainability & Use
Leaf Retention No
Fire Resistant Yes
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA