Shrubby St. Johnswort (Prolificum)

The Shrubby St. Johnswort (Prolificum) is generally described as a perennial shrub or subshrub. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The Shrubby St. Johnswort (Prolificum) has green foliage and inconspicuous yellow flowers, with a moderate amount of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the summer and continuing until summer. Leaves are not retained year to year. The Shrubby St. Johnswort (Prolificum) has a moderate life span relative to most other plant species and a moderate growth rate. At maturity, the typical Shrubby St. Johnswort (Prolificum) will reach up to 3.2 feet high, with a maximum height at 20 years of 0 inches.

The Shrubby St. Johnswort (Prolificum) is not commonly available from nurseries, garden stores and other plant dealers and distributors. It can be propagated by 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 -28°F. has low tolerance to drought and restricted water conditions.

Plant Basics
Growth Rate Moderate
General Type Shrub, Subshrub
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability No Known Source
Physical Characteristics
Bloom Period Late Spring
Displays Fall Colors No
Shape/Growth Form Single Crown
Drought Tolerance Low
Shade Tolerance Intermediate
Height When Mature 3.2
Vegetative Spread None
Flower Color Yellow
Flower Conspicuousness Yes
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Summer
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Sprigs
Moisture Requirements High
Cold Stratification Required No
Minimum Temperature -28
Soil Depth for Roots 10
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Slow
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 4.8–7.2 pH
Precipitation Range 30–30 inches/yr
Planting Density 4800–7000 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 10
Minimum Frost-Free Days 100 day(s)
Salinity Tolerance None
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention No
Fire Resistant No
Causes Livestock Bloating None

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