The Common Sage Plant and its Characteristics

The common sage, garden sage, sage plant, or just sage has the scientific name of Salvia Officinalis and is classified as a “subshrub” or a short woody plant or dwarf shrub. It is an evergreen perennial with woody stems, grayish leaves, and blue to purple flowers. It is a member of the mint family Lamiaceae and originated in the Mediterranean region. However, it has been naturalized in almost all parts of the world and has a long history of culinary and medicinal use. However, in modern times, it usually serves as an ornamental garden plant.

The common sage grows to a height of around 2 feet and flowers in late spring or summer. The leaves are very greenish and rugose on the upper side while being nearly white underneath due to the leaf containing many short soft hairs.

The leaves of the common sage are used as a culinary herb with a savory and slightly peppery flavor. It appears in many European and Middle Eastern cuisines especially with fish dishes and is traditionally served with sage and onion stuffing to accompany roast turkey or chicken during the holidays. The sage herb is also used for various pork and sausage dishes and stuffing. However, many chefs consider sage herb as more of a novelty than a common herb.

Common sage is grown in parts of Europe for distillation of an essential oil for culinary use and mixed with health products. However, there is still no clear evidence that essential sage oils have any real beneficial effect on human health.

Varieties of Sage Plants

Now considered more as an ornamental plant rather than a culinary herb, the common sage can grow almost in any favorable condition in any weather in any garden. Though commonly growing to a height of 2 feet, many other varieties are shorter or more compact. As such they are valued as small ornamental flowering shrubs, rather than for their herbal properties. Some varieties provide low ground cover, especially in sunny dry environments. Like its mint cousins, they can be killed by cold and overly wet winter especially if the soil is not well drained and excess water becomes stagnant. All sage species are easily propagated from summer cuttings while some varieties can be produced from seeds.

Some of the more common varieties of sage plants include:

• ‘Alba’ white flower
• ‘Aurea’ Golden Sage
• ‘Berggarten’ cultivar with large leaves, which rarely blooms, extending the useful life of the leaves
• ‘Extrakta’ has leaves with higher oil concentrations
• ‘Icterina’ cultivar with yellow-green variegated leaves (Royal Horticultural Society’s Award of Garden Merit)
• ‘Lavandulaefolia’ small leaf cultivar
• ‘Purpurascens’ (Purpurea) purple-leafed cultivar (Royal Horticultural Society’s Award of Garden Merit)
• ‘Tricolor’ cultivar with white, purple and green variegated leaves

How to Care for Sage Plants

Light

For sunlight, the common sage plant can thrive in medium to a full sunlight exposure. If you are growing Sage in a shady area, make sure that the plant still gets a few hours of sun. If growing sage indoors, place your sage pot near a sunny window.

Because the sage plant is native to the temperate regions of the Mediterranean, the plant prefers as much sunlight as possible and hot temperatures. It can even thrive in a desert environment, so this means that high humidity can cause issues for the plant. However, be sure to observe the plant for signs of extreme heat or wind damage, as any plant that gets excessive heat will certainly die out. Still, sage plants do not do well in cold temperatures, meaning anything less than -7°C. If temperatures fall below this, plant your Sage in containers so that they can be transferred indoors or inside a shed where it can be warmer and away from the cold. ​

Water

The common sage is tolerant even in near drought situations, and even when the leaves look wilted, a little water perks up the entire plant as soon as it is watered. Wait until the top soil is completely dry before giving it a thorough watering.

In the early stages of growth though, water your white sage plant more often. ​When the top of the soil feels dry to the touch, water the potted plant until it starts to run through the drainage holes or until water has permeated about 12 inches deep in the soil. 

Soil

Sage will grow almost anywhere in any weather, but it provides the most beautiful leaves to look at when it receives a lot of sunlight. This evergreen shrub is hardy and because of its affinity for well-drained garden soil, it can perform well in containers. They also thrive well in soil shared with carrots and tomatoes. They also make good ornamental plants for any shape of landscaping as well as with spring and flower arrangements.

Sage can prove challenging when planted by seed, but it is very easy to grow from cuttings or by the method of “layering.” But, regardless of which propagation method you choose, plant young sage plants only after the ground temperature hits 12°C or more, one to two weeks before the last frost.

Sage thrives in well-drained, sandy, and loamy soil; it prefers a pH between 6.0 and 7.0. Resist the temptation to over-fertilize because while the plant might grow a little faster, its flavor and leaf color will be less intense. The common sage grows in a round, bush-like fashion, so individual plants should be spaced from 24 inches to 36 inches apart. You can also plant sage in soil shared with carrots, strawberries, tomatoes, and cabbage. The sage seems to grow well together with these plants. You don’t need all these mentioned since one is enough, though your garden would look nice to have them all. Because the beautiful blossoms attract pollinators, let a couple of your sage plants go to flower. Sage plants will also grow well when planted in companionship with California Buckwheat, Black Sage, Hollyleaf Cherry, Sugar Bush, Lemonade Berry, and California Sagebrush. ​

Common sage seeds are plentiful in the seed pods of the plant but will germinate poorly. To increase the chances of germination, plant the seeds indoors and sow them no deeper than an 8th of an inch from the surface of the soil. You can also surface-sow as sage seeds prefer light when germinating. ​ It will take around 2-3 weeks for the seedlings to appear. You will know that your sage seedlings are ready for transplanting when they have 2-4 sets of true leaves. Try to transplant the new plant so they can get as much sunlight as possible. It will be helpful if they are planted in a container or near a wall in a ground-bound garden so sunlight reflects the new plant. But after all, is said and done, since the sage almost has the same characteristics as the common cactus, your best choice for container soil is a cactus potting soil mix. If growing in a container, be sure it’s one with ample drainage holes in the bottom.

Fertilizer

During the spring and summer, use a liquid fertilizer only once a month when watering your sage plant to supplement growth as the plants develop. Sage doesn’t really need a lot of fertilizer, and if you persist using too much, the plant may grow faster but the leaves will not look as attractive. Compost may help but is not necessary with sage plants since they thrive in cactus characteristics-soil. Mulching is not needed when planting sage, though they can be placed sparingly in the soil during the winter months so they absorb excess moisture because of the cold and frost.

Pruning

If you are planting common Sage for ornamental purposes, very little pruning is needed due to the plant’s cactus-like characteristics. The plant will grow to a height of about 1 to 2 feet and so will need very little pruning, except when dead leaves or stems need to be removed if any. If the sage plant is planted alongside other companion herbs or plants, a little trimming and pruning may be needed if the stems start growing in clumps over the other plants. However, if the plant is spaced away from the companion plants, no pruning is necessary. If you decide to prune the sage plant to shape it, the stems and leaves may not grow into their usual height and beauty.

If necessary, sage plants can be pruned in early Spring to promote new growth, or after flowering in the summer. Sage will become very woody within 3-4 years of planting and should be replaced with new plants.

Propagation and Repotting Guide

The common sage is usually propagated from seed, although cuttings, divisions, and air layering can also be used successfully as propagation and re-potting methods. The planting site should be warm, dry, and protected from the wind. Seeds should be sown after all danger of frost has passed leaving around 9 inches between seeds. Fertilizer may be added to the soil prior to planting to aid development, but only once since sage plants do not require much fertilizer. Plants should be thinned to a final spacing of around 18 inches. 

Propagate from cuttings.Clip a three-inch cutting from the very tip of a stem, apply rooting hormone on the exposed portion of the stem, and plant it in either sterile soil or vermiculite. Roots will emerge within six weeks. Transfer to a small pot, let the root ball form, and then transfer to a larger pot or directly to the ground garden. 

Propagate by layering. Take a long sage stem and carefully secure it along the soil with wire, leaving four inches of the tip free. Make sure the pinned portion is directly touching the soil. Roots will start to form along the stem in just one month. Cut away the newly rooted plant from the main plant and transfer elsewhere to a larger pot or to your ground-bound garden.

Harvesting and Storage

Although the common sage plant is an ornamental plant, for those who want to harvest occasionally to use the leaves as herbs, take note that in areas in which the sage plant is perennial, harvest sage only lightly during its first year of growth. In subsequent years, harvest sage as you need it, even all-year round. Cut an entire stem if desired, or just pinch off one leaf at a time. To give new foliage time to fully mature, leave off for 2 months between your last big harvest and the first frost of the season. Dry harvested sage by hanging bunches of stems upside-down. Strip the dry leaves from the stem and store in an airtight container. Keep the flowers on the stems to cultivate pretty pods that work well in dried herb arrangements.

Common Problems (Pests and Diseases) and How to Cure Them

Diseases

Crown Gall (Agrobacterium Tumefaciens). Usually shows symptoms of galls of various sizes in the roots and root crown below the soil line. Galls can also and occasionally grow on the stems. These galls are initially light-colored bulges that grow larger and then darken. The galls may either be soft, spongy, or hard and if galling is severe and girdles the stem then the plant may dry out and die. The cause of crown gall is from a bacterium and these can enter the plant through wounds and slices. Plant only disease-free material if you purchased your sage from a plant center and check out any sage you ask a friend or your sibling’s garden. Plant sage in well-draining soils and avoid wounding the plants as much as possible

Mint Rust (Puccinia Menthae). Usually show symptoms of small, dusty, bright orange, yellow or brown pustules on undersides of leaves, while new shoots may be pale and distorted. Large areas of leaf tissue will die and leaves may drop off suddenly from the plant. The cause of mint rust is a fungus that has spread from nearby mint or companion plants. Infected plants and rhizomes should be removed to prevent spreading. Heat treatment of roots may help to control the disease. The roots can be immersed in hot water at 44°C for 10 minutes, cooled using cool water and then planted as usual.

Powdery Mildew. Because sage likes low humidity and high temperatures, it is susceptible to mildew if put in high humidity environments or when overexposed to humid conditions during winter. You can prevent most if not all mildew issues simply by avoiding high humidity.

Anthracnose. Small, water-soaked spots on the aboveground parts. Turns a light color and may cause leaves to suddenly drop off. Forms elongated tan cankers because it is caused by fungus. To control, simply rotate your sage plants every two years. Do not cultivate when plants are wet. Remove and destroy diseased plants right away. 

Bacterial Soft Rot. Soft decay of the fleshy tissues, causing them to become slimy or watery. Shoots will wilt and blacken at the base. To control, remove all diseased plants very quickly. Avoid injury to plants as this may cause the disease to enter through the cut. Keep the soil as acidic as the plants can tolerate by raising the pH levels a little. 

Bacterial Wilt. No yellowing or other physical signs will occur, but plants will slowly and suddenly wilt and die. Stem sap produces strings while the vascular system turns brown. To control, remove diseased plants very quickly and avoid injury to plants. Keep the soil as acidic as the plants can tolerate by raising the pH levels only a bit. 

Black Spot. Black circles form on both sides of the leaves that can be up to half an inch in diameter, with indistinct and fuzzy edges. The tissue around the spots turns yellow and the leaves will drop off because the black spot is a fungus. To control, space plants to allow for good ventilation and never cultivate the soil when plants are wet. You can use heavy mulching, in this case, to help control or remove the disease. Remove diseased leaves promptly and water the sage plants only in the morning. 

Botrytis Blight. This disease leaves small yellow, orange, or brown splotches on the leaves, flowers, roots, and even bulbs. Once it spreads, the plants become coated with fuzzy, gray mold and hard, black blisters on the plants stems because the disease is a fungus. To control, remove all yellowing foliage and dead flowers right away.

Pests

Sucking Insects. Spray soft-bodied and sucking insects such as mites, thrips, aphids, spittlebugs and whiteflies with a light insecticidal soap. Although you can use homemade soap sprays, commercial sprays are milder and safer for plants. Spray the Sage thoroughly, coating the entire plant, including the tops and bottoms of leaves. Repeat as needed every four to seven days. Insecticidal soap sprays are less toxic than conventional pesticides because they kill only on contact and have no residual effect. However, the product kills all insects it contacts. Use soap spray only when necessary and only when you see possible sucking insects on the plant. Take note that beneficial insects like bees and wasps that help pollinate the plants can die off as well if you keep spraying indiscriminately.

Slugs. Slugs are easy to spot by the slimy trail they leave behind and by the ragged holes they chew in sage leaves, with the outcome of having ugly leaves filled with jagged holes. Commercial slug baits are effective for serious infestations. However, try less invasive treatments first because slug baits can be highly toxic. Remove slugs by hand if the infestation is light or create a simple trap by laying small boards or grapefruit halves near the plants. Check the traps every morning and dispose of the slugs hiding underneath, but be sure to kill the slugs first before disposing of them, lest they crawl out of the trash and infect another plant or garden. You can also surround the Sage with abrasive substances that will tear the slugs’ thin skin, such as used coffee grounds, wood ash, tiny pebbles, or coarse sand.

Caterpillars. These are the larval form of moths and butterflies and are destructive pests that can strip a sage plant quickly. Hand-picking the plump caterpillar pests is the safest and most effective treatment. Just remove the caterpillars and step on them or drop them in a bucket of soapy water. You can treat young, recently hatched caterpillars with Bacillus thuringiensis, an organic bacterial product also known as Bt. Bacillus thuringiensis attracts the caterpillars and will feed on the substance and die, usually within 48 hours. Bt is nontoxic to humans and animals as well as other beneficial insects such as bees and wasps. It is considered safe for the environment.

Things to Keep in Mind When Growing Sage Trees

Biological Controls

Harmful insects and caterpillars have natural enemies, including lady beetles, lacewing larvae, pirate bugs and parasitic wasps. The best way to maintain a healthy population of beneficial insects is to avoid conventional pesticides, which indiscriminately kills off all insects, both good and bad. Often, elimination of beneficial insects results in serious outbreaks of harmful pests, making the problem even worse. Use pesticides only after exhausting all other means and treat only serious infestations. Apply pesticides strictly according to label recommendations, and never on a windy day.

Cultural Controls

Naturally, healthy sage plants will be able to withstand pests better than unhealthy or stressed plants. Water Sage deeply during dry weather, but let the soil dry between watering before watering again as sage is a drought-tolerant plant that can become damaged in waterlogged soil. Fertilize lightly because overfeeding causes sage to become weak, floppy and more susceptible to pests and disease, the leaves will become ugly. Remove blooms as soon as they wilt and prune dead or diseased plant parts. Provide ample spacing around plants to provide air circulation and keep the area around the plant free of weeds, leaves and other debris.