Genus: Origanum rotundifolium
• Hardy to Zone 7
Most people are quite familiar with the many culinary cultivars of Origanum vulgare (i.e. ‘Italian’ oregano), and marjoram (‘Pot’ marjoram); but, less is known about an interesting species from Turkey, Origanum rotundifolium. This is a delightful mounding species that is found in rocky, well-drained areas with full sun exposure. It forms an evergreen creeping mat when dormant but eventually reaches 6 to 10 inches in height from short, woody, wiry stems. These are covered with a series of clasping pairs of rounded, slightly aromatic, bluish-green, glabrous leaves. In fact, the only common name I can find for this plant is roundleaf oregano.
It is a superb rockery or garden wall plant with its neat mounding habit and unusual, attractive flowering habit. The inconspicuous pale pink or white flowers are camouflaged by large, 1-inch or more, yellowish-green, papery, hop-like flower bracts. These bracts tend to weigh down the flowering stems to form a wonderful and decorative cascading effect. These stems may be cut for fresh flowers or, better yet, for drying as unique everlastings. The only pity is that they are short in length (4 to 8 inches), which limits them for use in large flower arranging; but they’re excellent as unusual color accents in herbal wreaths.
Roundleaf oregano is quite promiscuous and hybridizes freely from random garden romances which have lead to such notable hybrids as Origanum x ‘Kent Beauty’ (with pinkish tipped bracts) and Origanum x ‘Barbara Tingey’ (with even darker pink or flushed colored bracts).
These plants are easy to grow if given full sun exposure and extremely good drainage as provided by a garden wall planting. Although hardy to Zone 7, I find they are able to take lower temperatures if they are not excessively wet during the winter. The parent species, O. rotundifolium, seems to be much more robust and hardier than the subsequent hybrids.
Pot culture — especially hanging baskets — is an excellent way to grow and display this attractive oregano species. There is a marvelous collection of Origanum species and cultivars in the alpine greenhouses of the Cambridge Botanic Gardens in England.
Propagation is by vegetative cuttings taken early in the spring when just breaking dormancy, or allowing the plant to self sow. The seed is miniscule and must be aggressively extricated from the corolla; but it germinates easily.