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Gemo St. John's Wort
Hypericum kalmianum 'Gemo'
Height: 3 feet
Spread: 3 feet
Sunlight:
Hardiness Zone: 4a
Other Names: Kalm's St. John's Wort
Brand: Gertens
Description:
Beautiful bright yellow buttercups flowers with bushy stamens; green leaves are narrow and willow-like; widely adaptable but thrives in moist, well-drained soil
Ornamental Features
Gemo St. John's Wort has masses of beautiful yellow buttercup flowers at the ends of the branches from mid summer to mid fall, which are most effective when planted in groupings. The flowers are excellent for cutting. It has green deciduous foliage. The narrow leaves do not develop any appreciable fall color.
Landscape Attributes
Gemo St. John's Wort is a multi-stemmed deciduous shrub with an upright spreading habit of growth. Its relatively fine texture sets it apart from other landscape plants with less refined foliage.
This shrub will require occasional maintenance and upkeep, and should only be pruned after flowering to avoid removing any of the current season's flowers. It has no significant negative characteristics.
Gemo St. John's Wort is recommended for the following landscape applications;
- Mass Planting
- General Garden Use
- Groundcover
- Naturalizing And Woodland Gardens
- Container Planting
Planting & Growing
Gemo St. John's Wort will grow to be about 3 feet tall at maturity, with a spread of 3 feet. It tends to fill out right to the ground and therefore doesn't necessarily require facer plants in front. It grows at a medium rate, and under ideal conditions can be expected to live for approximately 5 years.
This shrub does best in full sun to partial shade. It is very adaptable to both dry and moist growing conditions, but will not tolerate any standing water. It is particular about its soil conditions, with a strong preference for rich, alkaline soils. It is highly tolerant of urban pollution and will even thrive in inner city environments. This is a selection of a native North American species. It can be propagated by division; however, as a cultivated variety, be aware that it may be subject to certain restrictions or prohibitions on propagation.
Gemo St. John's Wort makes a fine choice for the outdoor landscape, but it is also well-suited for use in outdoor pots and containers. With its upright habit of growth, it is best suited for use as a 'thriller' in the 'spiller-thriller-filler' container combination; plant it near the center of the pot, surrounded by smaller plants and those that spill over the edges. It is even sizeable enough that it can be grown alone in a suitable container. Note that when grown in a container, it may not perform exactly as indicated on the tag - this is to be expected. Also note that when growing plants in outdoor containers and baskets, they may require more frequent waterings than they would in the yard or garden. Be aware that in our climate, most plants cannot be expected to survive the winter if left in containers outdoors, and this plant is no exception. Contact our experts for more information on how to protect it over the winter months.
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