(Silver Horehound) Wooly white hairs on the underside of gray-green foliage help conserve moisture and give this drought resistant groundcover a silvery appearance. This explains the plant's common name as well as the second word in its botanical name, incanum, which means "hoary" (whitish-gray) in Latin.
The downward curving leaves of Marrubium incanum have a pleasant, suede-like texture and attractively scalloped and toothed margins. During summer, they are topped by fragrant whorls of tiny, pale lilac flowers that fade to white. Similar to so many nectar-rich plants in the mint family, it is a favorite among bees.
This Mediterranean native tolerates cold and heat as well as dry spells. In the wild of its homelands, including Italy, it appears in grassy areas beside agricultural fields along with wildflowers like Red Poppy. Various types of Marrubium have a long history of medicinal use, but this one is primarily valued as a pollinator plant and resilient, ornamental perennial.
For best growth, give Silver Horehound full sun, well-drained soil, and average watering based on local precipitation.
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Here are some guidelines for success with this plant in your garden.
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This plant needs or tolerates more than six hours of intense sunlight daily. Many Salvias only thrive in wide-open locations where they receive long hours of full sun. However, full-sun species sometimes tolerate a bit of partial shade. Or a Salvia that loves partial shade may be amenable to spending part of its time in full sun.
In general, this sun/shade adaptability shows up in Salvias that do best in cooler climates when grown in full sun and thrive in hot climates when partial shade is available. So full-sun Salvias sometimes are also categorized as partial-shade plants and vice versa.
This plant can handle extreme heat.
Full-sun Salvias that don’t like any shade are among the most heat tolerant. Heat-loving Salvias also are often drought tolerant. Moisture-conserving features, such as fuzzy leaves, help them stay perky at high temperatures.
Heat-tolerant Salvias are fine choices for western and southern exposures.
This plant grows well in an outdoor container, such as on a patio.
Some containerized Salvias leaf out and flower year after year following a period of dormancy. Annuals in containers may die back and appear to grow again when they reseed.
During extreme heat, check the soil in container plantings once or twice daily to be sure it doesn't completely dry out. Feel its surface for coolness, then gently poke a finger into the soil to check for dryness.
This herbaceous plant is known for its use in folk remedies.
Salvias have been used as healing herbs by a wide variety of cultures in the Americas, Europe and Asia. The genus name is from the Latin term “salvare,” which means to save.
When considering application of an herbal remedy to treat a medical problem, be sure to consult a physician first.
When growing a fragrance garden, this is a good selection.
Most Salvias have pleasant scents, but some are intoxicatingly fragrant. Some are short enough for border plantings that release a heady perfume as you brush against them when strolling along a path. Other taller types make good landscape highlights, particularly by doors where their scent can be enjoyed on entry and exit.
To create a harmonious landscape plan, it is important to consider the heights of individual plants.
Height also affects function. Short Salvias often make excellent ground covers that conserve soil moisture and discourage weeds while also brightening your yard. Medium-height Salvias, such as ones 36 inches tall, often are ideal border plants. A tall Salvia planted singly can highlight a landscape; multiple plantings can form an attractive screen.
Plant this herbaceous species in the USDA Zones where it grows as a perennial, returning year after year.
After dying back to the ground at frost, herbaceous perennials emerge in the Spring with soft, new growth. A Salvia that is perennial in one region, may be an annual in another depending on local conditions, such as winter temperatures.
If you live in USDA Zone 5, for example, Salvias in our catalog cited as growing well in Zone 5 or lower will be perennial. Those cited as doing well in Zones 6 or higher may do well in Zone 5, but generally will act like annuals coming back from seed instead of the parent plant’s roots.
By considering the width of a plant, you can determine how many to place in a row or what other plants to grow with it.
For example, a narrow, moderate-height Salvia may look good interplanted with bushier species, kind of like Mutt and Jeff.
In contrast, wide-spreading Salvias are economical for hiding lengths of wall and fence or for creating hedge-like divisions in a yard.
Plant hardiness Zones defined by the U.S. Department of Agriculture tell you the minimum temperatures a plant can withstand in your garden. The USDA divides the nation into winter climate areas from coldest (Zone 1) to warmest (Zone 11).
However, it is sometimes possible to grow a Zone 6 Salvia as a perennial in Zone 5 if you provide preferential care, such as winter mulching and a location sheltered from harsh winds. In contrast, a Zone 9 Salvia may act like a perennial in Zone 10 if given a bit of shade or extra water.
This plant needs regular watering based on what is appropriate to your local conditions.
In some extremely hot, arid climates, this may mean daily watering in Summer. Although many drought-resistant Salvias survive on little to no watering due to local rainfall and deep roots meeting their moisture needs, others need regular doses. The size and frequency of the dose depends on your climate.
In the right locale, this plant survives and thrives despite minimal summer water.
Drought resistance is an important characteristic of xeriscapic – dry landscape – plants, a category that includes a multitude of Salvias. Many low-water Salvias are native to parts of the world with little rainfall all year or regions where summers are dry and winters are wet.
Nevertheless, there are also drought-resistant Salvias for places such as Florida where winters are dry and summers are wet.
Honeybees love this plant’s nectar. As a honeybee burrows down into a Salvia’s nectar-rich flowers to reach dinner, it accidentally gathers pollen and drops it on the stigma of that blossom or of ones on other nearby Salvias. Fertilization results in seed production.
By growing honeybee favorites, you attract these helpful pollinators to all your flowering plants and increase productivity
Unless local forage is in short supply, most deer likely will avoid this plant.
It appears that deer dislike Salvias, in general, due to their volatile oils that make the plants so fragrant and savory in cooking. However, the only completely deer-proof plants are the ones grown beyond reach.
(Uruguayan Firecracker Plant) Mint-green foliage felted with a covering of fine hairs provides a cooling backdrop to the hot orange tubular flowers of this long-blooming member of the acanthus family (Acanthaceae).
(Cedros Island Sage) From the Island of Cedars off the coast of Baja California Sur comes this delightful xeric sage with deep violet-blue flowers and silvery foliage. The square-shaped, 1-inch-long leaves are densely covered with downy, short, white hairs providing moisture retention.
(Silver Germander Sage) With its compact habit, brilliant silver-white leaves and large, sky blue flowers, this is an outstanding heat-tolerant choice for dry, sunny gardens. We consider this to be one of the finest short ground covers for these conditions.
(Greek Sage) Most of the dried culinary sage sold in the United States is Greek Sage. Frescoes on the island of Crete dated to 1400 BC depict this plant, which was used by the Phoenicians and Greeks for cooking and medicine. It is an ancient and beloved friend of mankind.
(Dandelion Leaf Sage) Brush or bruise the basal foliage of this Moroccan Salvia and it exudes a citrusy fragrance. Petite and heat tolerant, this is a sturdy, adaptable groundcover.