(Oxford Blue Gentian Sage) Only Salvia patens 'Blue Angel' comes close to the rich gentian blue of this sage from Central Mexico. Oxford Blue also grows taller and spreads wider than Blue Angel.
Well branched and compact, this Gentian Sage is reliably perennial in USDA Zones 8 to 11. Its lustrous, true blue flowers are 2 1/2 inches long and bloom from summer into fall. They make it a worth growing as a summer bedding plant in areas with colder winters.
Oxford Blue likes regular watering and rich, well-drained soil. It does fine in full sun or partial shade and can handle moist corners of the yard. Use it as a path edging, border, groundcover or container plant.
German botanist Karl Hartweg discovered the Salvia patens species in 1838. British horticulturist Graham Stuart Thomas later called it "the best plant in cultivation."
True blue is not a part of the color spectrum that hummingbirds favor, but they do love the rich nectar of the Gentian Sages. To ensure that hummingbirds stop by to tank up, mix Gentians with red flowered species.
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Learn more about how we analyze plant colors
We based our analysis of this plant’s floral and foliar color on the internationally standardized color system published by the U.K.’s Royal Horticultural Society. Called the RHS Large Colour Charts, this publication is a boxed set of color swatches arranged in fans and containing all the colors that RHS has identified in horticulture. RHS gives each color a common name and code number.
Each swatch has a small hole punched into it. We place the swatch over a flower petal and compare the blossom’s color to that of the card. When using RHS colors to compare plants that you want to combine in a flowerbed, in bouquets or in some other manner, RHS says to view them indoors in north light. If you are matching our digital swatches to flowers already in your garden, pluck two or three fully open blossoms of each plant that requires analysis.
You may find that the plant you receive from FBTS varies somewhat in color from what appears in our color analysis or our photograph due to a number of factors, including:
- Variations in photographic colors based on lighting level at different times of day
- Differences in the resolution of digital screens
- Seasonal changes in plant color due to changes in temperature and plant cycle and
- pH or soil chemistry that varies from one locale to another and causes color shifts.
Finally, RHS notes that you shouldn’t attempt color matching when your eyes are fatigued.
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 thrives when planted where it will receive morning sun followed by afternoon shade, such as on the eastern side of a house. Make sure it isn’t exposed to midday and afternoon sun, which can damage tender leaves during the summer when sunlight is more intense due to being more direct.
Although midday is when sunlight is most direct, it takes time for the atmosphere to heat up and for heat to peak at sometime in the afternoon. Salvias that prefer cooler temperatures are protected by afternoon shade during the hottest time of year.
This plant grows well in partial shade, such as the kind on the edge of woodlands or under deciduous trees with breaks in the foliage through which dappled sunlight penetrates. Many Salvias thrive in partial shade, including ones that spend part of their day in full sunlight. Some species need partial shade to overcome severe heat and dry soil.
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.
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.
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.
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 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.
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.
This plant reaches peak bloom in Fall or flowers for much of the season.
It may begin flowering much earlier in the year. Bloom time for some Salvias lasts from Spring till first frost. Others begin flowering in Summer and continue into Fall. There are also Salvias that don’t bloom until late Fall and continue into Winter if grown in mild-Winter areas.
There is a great deal of overlap in blooming seasons for Salvias.
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.
Based on our experience and reports from customers, hummingbirds (Trochilidae spp.) love this plant.
Hummingbirds exist only in the Americas where their 300-plus species are particularly fond of the nectar in brightly colored Salvias from the Western Hemisphere. However, if favorites aren’t available, they dine on the nectar of most Salvias.
Hummingbirds repay thoughtful plantings by helping to pollinate your garden