Woody > Hypericum > Hypericum prolificum > Hypericum prolificum
Hypericum prolificum
Shrubby St. Johnswort
Origin: Introduced into cultivation in 1750. Native to New Jersey and Iowa.
| Family |
| Hypericaceae |
| Genus |
| Hypericum |
| Species |
| prolificum |
| Category |
| Woody |
| Type |
| Shrub (deciduous) |
| Pronunciation |
| USDA Hardiness Zone |
| 5 - 9 |
| Canadian Hardiness Zone |
| 9b - 5a |
| RHS Hardiness Zone |
| H4 - H7 |
| Temperature (°C) |
| -30 |
| Temperature (°F) |
| -20 to (-30) |
| Height |
| 1.3 m |
| Spread |
| 1.3 m |
Photographs
Cultivars
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Description and Growing Information
Flowering Period
| General Description |
| A loose formed, but low mounded shrub with delicate branching and linear leaves. Flowers are bright yellow and quite prolific. |
| Landscape |
| Best suited to mass planting for full effect. Ideal for large scale commercial plantings since it is relatively care free. |
| Cultivation |
| Loosen up soil, remove rocks and weeds, does well in dry soils, full sun. |
| Shape |
| Dense, rounded form, small. |
| Growth |
| Slow |
| ID Characteristic |
| A small shrub with opposite leaf arrangement, and small linear leaves. Bright yellow flowers with a post persistent capsule fruit. |
| Pests |
| Hypericum rust can damage some species and cultivars otherwise it is a relatively problem free plant. |
| Habitat |
| New Jersey and Iowa to Georgia. |
| Bark/Stem Description |
| Older stems are light brown and exfoliating and tend to become gnarled with age. |
| Leaf Description |
| Opposite leaf arrangement. Simple, narrow oblong to oblanceolate, 2.5 - 7.6 cm long, 0.6 - 1.2 cm wide. Obtuse, dark lustrous green or bluish green above, no noticeable autumn colour. |
| Flower Description |
| 1.91 - 2.54 cm in diameter, bright yellow, flowers late June to August, borne on auxiliary and terminal flowered cymes. |
| Fruit Description |
| Dry, dehiscent 3 valve capsule, persistent all winter, brown, offers a good identification feature, could be used for dried arrangements. |
| Colour Description |
| Dark lustrous green in summer, possibly considered bluish green. There is no noticeable autumn colour. Bark is light brown, flowers are clear yellow. |
| Texture Description |
| Medium. |
| Notable Specimens |
| The Gardens of Fanshawe College, London, Ontario. |
| Propagation |
| Softwood cuttings taken in June - July root easily if treated with 1000ppm of IBA and placed in sand undermist. Seed germinates without pretreatment. |
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