It is a dwarf deciduous shrub growing to 25 cm tall by 30 cm broad, with small oval grey-green leaves, and clusters of star-shaped yellow flowers with prominent stamens in summer. As it requires sharp drainage to prevent winter rot, it is a suitable subject for the rockery or alpine garden. It increases by creeping lateral stems and self-seeds readily.
I. Appearance and Characteristics
Hypericum olympicum, commonly known as the Mount Olympus St. John’s wort, is a species of flowering plant in the family Hypericaceae found in the Balkans and Turkey and introduced to western Europe.
The species is native to Southeastern Serbia, Macedonia, Albania, Bulgaria, Greece (excluding Crete and western Aegean islands), and northwestern Turkey. The species was first introduced to England in 1676 by Sir George Wheeler from seeds found in Turkey, and it was cultivated at the Oxford Botanical Garden. The species has also been recorded as establishing itself in Belgium and France, where it is considered an invasive species.
It can be found in sandy, stony, and sometimes grassy places or among rocks in open ground, or in pine woodland at elevations of 0–2000 m.
H. olympicum was first described in Carolus Linnaeus’s Species Plantarum in 1753.
The species is a shrub or subshrub that grows to be 0.1–0.55 meters (0.33–1.80 ft) tall. It can grow in an erect to decumbent manner, or rarely prostate. It can have few to numerous stems, and it is caespitose, occasionally rooting, and unbranched below its flowers. The stems’ internodes are 5–15 millimeters (0.20–0.59 in) long, and can be either short or longer than the leaves.
The leaves are spreading to erect, and are more or less glaucous, and are 5–30 by 2–12 millimeters (0.197 in–1.181 in × 0.079 in–0.472 in) in size. They are elliptic or rarely lanceolate-elliptic, are concolorous and thinly coriaceous. Their apex is acute to subacute or rounded-obtuse, with a rounded or cuneate base. They have 0-3 pairs of lateral veins and are unbranched (at least visibly). The laminar glands are pale and not prominent, and the intramarginal glands are black, small, and few in number.
The plant is usually 1–5 flowered, but can have up to nine flowers that grow from three nodes, and rarely from one lower node. Their pedicels are 2–4 millimeters (0.079–0.157 in) long and rather stout. The bracts are reduced-foliar, are broadly imbricate, and lack black glands, and the bracteoles are similar but smaller in size.
The flowers are 30–65 millimeters (1.2–2.6 in) in diameter, and their buds are ovoid-pyramidal and rounded. The sepals are either unequal or subequal, are broadly imbricate, and are paler than the leaves. They are 6–16 by 3–12 millimeters (0.24 in–0.63 in × 0.12 in–0.47 in), and are broadly ovate to lanceolate, and have a rounded base.
They are entire, large, pointed, and persistent in fruit. They have 9–15 veins that are branching. Their laminar glands are pale and linear, and there are sometimes a few that are black and punctiform. Their marginal glands are normally absent, but there can rarely be one or two black apical ones. Their petals are golden or pale yellow, and can have a tinge or lines of red.
They are 15–30 by 8–12 millimeters (0.59 in–1.18 in × 0.31 in–0.47 in), and there are around 2 times as many of them as sepals. They are rounded and their apiculus is short, and they are acute to obtuse. Their laminar glands are pale and linear, and their marginal glands are absent or black, and there are one to around seven of them. There are around 65–125 (0.9 times as many sepals) stamens that are 14–25 millimeters (0.55–0.98 in) long. The ovaries are 3 by 2.5 millimeters (0.118 in × 0.098 in) and are broadly ovoid, the styles are 18–23 millimeters (0.71–0.91 in) and there are six to eight times as many as the ovaries.
The seed capsule is 5–10 by 4–8 millimetres (0.20 in–0.39 in × 0.16 in–0.31 in) and is shorter than the sepals, and is shaped broadly oval-like to spherical. The seeds are a dark brown color, and are around 1.8 millimetres (0.071 in) with shallow testa.
Because of its large, showy flowers, relative hardiness, and dense shape, the species is valued among gardeners, specifically in the United Kingdom. It has been noted for these properties and won several awards, including in 1930, under the incorrect name of H. fragile, winning the Royal Horticultural Society’s Award of Garden Merit. While the species is not at all harmful to humans, it can be toxic to dogs, cats, and horses, and should be planted away from such animals.
It can be grown in chalk, clay, sand, or loam, and requires moist ground, but with sharp drainage. As it requires sharp drainage to prevent winter rot, it is a suitable subject for the rockery or alpine garden. The species requires pH to be between 6.1 and 7.8, which means it can tolerate both mildly acidic and mildly alkaline conditions. The plant usually takes 5–10 years to reach its full height, but much less than that to reach maturity.
The species should be planted in May or June, will flower from June to August, and cuttings should be taken from May to July.
II. How to Grow and Care
Sunlight
Mount olympus St. John’s wort needs sufficient sunlight but doesn’t tolerate direct light. Grow the plant in the shade of other plants or on a balcony away from strong, hard light. Expose it to more sunlight in the spring and fall to help it grow, but in the summer, place the potted plants in half-shaded places and mist them with water to cool the temperature and increase humidity. Otherwise, symptoms like drying leaf tips may appear.
Temperature
Plants of the Hypericum genus are widely distributed. They like warm, moist environments; the best temperature range for the plants is 20 to 26 ℃, but they can tolerate temperatures as low as -10 ℃. They require little water and endures drought, but don’t tolerate waterlogged soil. Avoid watering so frequently that the soil gets waterlogged.
Watering
It is a dwarf deciduous shrub growing to 25 cm tall by 30 cm broad, with small oval grey-green leaves, and clusters of star-shaped yellow flowers with prominent stamens in summer. As it requires sharp drainage to prevent winter rot, it is a suitable subject for the rockery or alpine garden. It increases by creeping lateral stems and self-seeds readily.
Soil
Mount olympus St. John’s wort can adapt to a wide range of soil types. It grows well in most common soils (except for heavy clay) and prefers sandy loam with good drainage. A slightly acidic loam with a 5.5-7.0 pH value is ideal. Mount olympus St. John’s wort is tolerant of barren soil and drought, but if the soil can’t drain water well, waterlogging can cause the roots to rot.
Fertilizing
Mount olympus St. John’s wort requires very little fertilizing. Usually, no additional fertilization is needed after the initial planting, unless obvious symptoms of slow growth appear. If that happens, apply some low-concentration balanced compound fertilizer (10-10-10 NPK ratio).
Planting Instructions
Plant mount olympus St. John’s wort in the early spring or early fall. Choose a cool, shaded place, such as within tree shade. Remember to clear the soil first and remove weeds. Dig a planting pit slightly shorter than the diameter of the root ball and 3 times wider. If you’re planting more than one sapling, avoid planting them too close, or low light and poor ventilation may result in powdery mildew.
Pile some soil around the root collar (the juncture of trunk and roots) to form a gentle slope, and this helps disperse water. After planting, press the soil firmly and water thoroughly. Note the distance between each
Some plants in the Hypericum genus have subterraneous rhizomes that tend to expand in all directions. To prevent excessive expansion, it’s a good idea to fence the planting spots or set brick perimeters around them to control their growth.
Pruning
Mount olympus St. John’s wort doesn’t need much pruning. To promote more lush growth, trim 1/5-1/4 of the total branch length by the end of spring or early summer, which promotes new branches to sprout. Mount olympus St. John’s wort buds and leaves both grow in pairs. Generally speaking, cutting one branch off promotes the pair of buds beneath the incision to develop into two branches.
For mount olympus St. John’s wort with robust growth and branches crossing inward, winter is the time for an overall pruning. As perennial herbaceous plants, you may just clip them flat with a sickle and they will revive. Mount olympus St. John’s wort has a short life span, so you can also consider getting new seedlings to replace the old ones once they start to decline.
Propagation
Found in rocky regions of Europe, mount olympus St. John’s wort is prized for its bright yellow flowers and medicinal qualities. For optimal propagation, utilize cuttings from healthy, non-flowering shoots for quick root development and establishment. The cuttings should be placed in well-draining soil, ensuring the lower nodes are buried while keeping the top leaves above the soil surface. A sunny location combined with regular watering will support the cutting until it fully roots, after which it can be transplanted to its final position.
III. Uses and Benefits
- Medical uses
H. olympicum f. olympicum is used alongside other Hypericum species in parts of rural Turkey as traditional folk medicine. Typically, its flowers are harvested and used to treat stomach aches, cuts, and burns.
- Other uses
Essential oils
H. olympicum contains numerous essential oil compounds, with the main components being (E)‐anethole (used as an aromatic substance), β‐farnesene (used as a constituent to essential oils), and spathulenol. Other components included germacrene D and (E)‐caryophyllene, as well as an unusually high amount of terpenes.
Antimicrobial
While as of 2019 extracts from the species are not currently used as antibacterials, they do contain antibacterial properties. Specifically, the plant contains new types of acylphloroglucinol that have been given the name olympicin after the species’ name.
Antidepressant
Similarly, as of 2019, H. olympicum is not widely used as an antidepressant in the way that Hypericum perforatum is, but it has been shown to have many similar or better antidepressant properties. Specifically, the amentoflavone in H. olympicum was shown to have previously unstudied antidepressant capabilities.
Anticancer
H. olympicum has been studied alongside other Hypericum species for their ability to suppress the growth of cancer in several ways. The species has been shown to have minor antigrowth effects on certain types of lung cancer, slowing the replication of cancerous cells in a laboratory setting. It has also been shown to help induce apoptosis in damaged cells because of the genotoxic properties of some of its chemical constituents. The species has not had any of its extracts approved for anticancer regimens.
Antioxidant
H. olympicum contains a smaller amount of flavonoids and tannins than other Hypericum species, but still displays significant antioxidizing capabilities, which suggests there are significant amounts of other undetected compounds in the plant.
