Jerusalem Sage: Growing Phlomis Fruticosa
Jerusalem sage is a flowering shrub that hummingbirds adore, and we do too! Our in-depth guide explains growing it in your garden.
Jerusalem sage is a lovely semi-perennial, drought-tolerant addition that adds splashes of bright yellow flowers to gardens. Growing Jerusalem sage for herb or flower is relatively easy, too, with the plant needing little care once it is established.
Also known scientifically as Phlomis fruticosa, Jerusalem sage originates in the Mediterranean, where it thrives in sandy and rocky soils along coastal cliffs and inclines. Much like many other Mediterranean herbs that flower, it finds homes in herb, meadow, and pollinator gardens in much of North America too.
One of the most extraordinary botanical characteristics this plant displays is its lovely pubescent stems and leaves that are soft to the touch. Another interesting characteristic is the plant’s function in culinary settings. While it’s not often the chosen sage for cooking, it works much like culinary sage.
So, let’s take a dive into this lovely perennial herb with a sunny flower! Here we’ll discuss the origins of its golden summer flower and talk about how you can grow it yourself.
Quick Care Guide
|Common Name||Jerusalem sage, Shrubby Jerusalem sage, Phlomis, lamp wicks, lamp wick plant|
|Scientific Name||Phlomis fruticosa|
|Height & Spread||Up to 3 feet tall and 5 feet wide|
|Light||Full sun to partial shade|
|Soil||Somewhat fertile, well-draining soil|
|Water||1 inch per week (sometimes less)|
|Pests & Diseases||Leafhoppers, fungus-resistant|
All About Jerusalem Sage Plants
Phlomis fruticosa is commonly known as shrubby Jerusalem sage, Phlomis, lamp wick plant, or Jerusalem sage. It originates in the Mediterranean region, primarily in Greece, Italy, Turkey, Albania, and areas of former Yugoslavia. Like many herbaceous perennials that flower in regions of North America, this plant tends to crop up in overgrazed and disturbed areas on the Mediterranean coasts.
The shrub consists of erect stems that reach up to 3 feet tall, spread 5 feet wide, and have wrinkled leaves that are ovate. Both the grayish-green leaves and stems are covered in fine hairs, giving them a very soft and light appearance in whatever landscape they grow in.
The growing season of Jerusalem sage occurs from spring through late fall, with a bloom time that begins in late spring and ends in late summer. It’s at this time that vibrant short spikes of yellow flowers emerge from multi-stemmed shrubs. Each spike has about 20 flowers lining the outside, and each flower looks somewhat like a snapdragon.
Phlomis fruticosa has a close relative in the same family, known botanically as Phlomis russeliana and commonly as Turkish sage. This plant has a similar native region but resides more in Turkey, Syria, and western parts of Asia. It is slightly shorter by about 1 foot, and the leaves are more pointed. The flower of this plant is much like that of fruticosa, though.
After the flowers die away on Jerusalem sage plants in winter, attractive seed heads remain, which offer not only an interesting sight in the garden but a habitat for insects and food for birds. When in bloom, the flowers are an excellent choice for a pollinator garden, with their nectar attracting numerous bees, hummingbirds, and butterflies.
Jerusalem sage leaves go well in soups and stews or mixed into butter and bread for a lovely flavor akin to culinary sage. Another aspect it shares with culinary sage (although each plant is in a different genus) is that it remains evergreen in temperate and subtropic regions.
The leaves on the upper half of the plant were used as lamp wicks by ancient peoples. In fact, the genus name, Phlomis is Greek for ‘flame,’ which could refer to its practical use or the brightness of its flower. It received the Award of Garden Merit from the Royal Horticultural Society, and it is so worth growing for its lovely flower color that shines in summer.
Care for Drought-Tolerant Phlomis
Growing Jerusalem sage is simple! Follow these guidelines, and you’ll have bright yellow flowers in your garden from late spring, through early summer, into autumn in most areas. Let’s discuss gardening this native of Turkey in your region.
Sun and Temperature
Phlomis fruticosa grows best in full sun but tolerates some light shade if full sun is inaccessible. 6 to 8 hours of full sun is best in most cases. However, in hotter regions, provide some light shade in the hard afternoon light. In cooler regions, anything less than full sun can produce leggy growth and stunt the plant through the growing season.
Jerusalem sage is hardy in USDA zones 8 through 10, but the plant remains semi-perennial in zones 5 through 7. In the arctic cold of zones 3 and 4, the plant may have trouble returning annually. It is winter hardy down to 23° Fahrenheit and tolerates high heat conditions, especially with a bit of shade to offset warmth. It takes on damage in extremes, however, with resulting affectation occurring on the grayish-green leaves in intense cold and intense full sun in extreme heat.
If you live near zone 10 or somewhere prone to heatwaves, provide light shade by planting it in a dappled sun area or moving taller plants nearby. In the cold, allow the foliage to die back in winter and provide a thick layer of mulch to keep the roots safe until blooms return in late spring.
Water and Humidity
While regular watering is necessary for Jerusalem sage plants shortly after transplanting, these drought-tolerant shrubs won’t need much afterward. As a baseline, about 1 inch of water per week is good, especially for those planted in full sun. During temperate seasons, it won’t be necessary to water beyond a couple of times a week.
Increase watering in early summer and late summer, and cut back in winter. Since Jerusalem sage is sensitive to cold, water slowly and deeply ahead of a freeze to about 3 to 4 inches below the soil line. Use either drip irrigation or soaker hoses. Careful hand watering is fine, too, as long as it is slow and focused at the base of the plant rather than its leaves.
Water in the morning or at dusk. Morning is preferable, as this will give the roots of Jerusalem sage plants time to absorb the water as the soil warms. The plant adapts to varying levels of humidity, ranging from fully drought-tolerant to the humidity of the Mediterranean coast.
Your Jerusalem sage needs semi-fertile, well-draining soil. You can amend the soil when you transplant in late spring or fall by adding a little bit of well-rotted compost to the planting site. If the native soil is compacted, aerate it and provide some agricultural sand or perlite to promote drainage. Once established, your plant will thrive in most soil types, provided they drain well. Phlomis fruticosa especially loves gravel as a growing medium. It has a wide pH tolerance, from mildly acidic to slightly alkaline.
Fertilizing Jerusalem Sage
Jerusalem sage plants don’t need fertilizer to thrive, but annually in fall, you can add well-rotted, fertile compost to the base of the plant on the soil’s surface to assist with nutrient replenishment. Compost contains basic and trace nutrients needed to support further growth in early spring.
Pruning Phlomis fruticosa
Jerusalem sage loves heavy pruning in fall. This allows for more vigorous growth in its late spring season. If you do not want the plant to spread and sprout in late spring due to explosions of attractive seed heads in winter, deadhead them as the blooms fade. Alternatively, you can cut them while they are in bloom and put them in floral arrangements to promote a second flower period.
Winter pruning, especially in colder regions outside the plant’s hardiness zone range, is very important. Cut the woody stalks of the plant to the ground with a sanitized pair of pruning shears. Then add a layer of mulch to its base to protect the roots. In USDA zones 8 to 10, mulch may not be necessary.
Jerusalem Sage Propagation
Propagation by seed is a much longer method to choose than propagation by division or softwood cuttings. In warm or temperate USDA zones, sow seeds in spring in starter trays (like our Epic 4-cell and 6-cells). In colder zones, wait until a few weeks before the last frost.
Keep the seeds at about 65° F. They’ll sprout in roughly 10 weeks. When they reach 3 to 4 inches tall, spend a couple of weeks gradually hardening them off, and plant them in the garden in an area where you want to attract butterflies, hummingbirds, and bees.
Break up these evergreen shrubs in your landscape by division in spring. This is one of the most important skills to know for perennial gardening. Look at the plant, and lightly mark a 4 to 6-inch circle in the garden with a shovel around the base of the plant.
Then use the shovel to gently pry the root ball above the garden soil. Search in the root ball for places where horizontal runners connect each stem of the plant. Carefully divide these to have more sage in your landscape. Cut them cleanly with a pruning knife – we recommend the Felco 322 snips – and transplant the sections in desired areas.
Mound layering is an excellent choice for propagating this evergreen too. Find a stem with soft green growth, and make a slight cut on that stem, keeping the stem intact. Then layer garden soil around and on top of the soft stem. In a few weeks, that stem should have developed roots. It can either be left to grow a whole new plant or transferred into another area where you’re gardening perennials.
Finally, softwood stem cuttings grow new plants. Search for stems on the upper half of the plants with new green growth at their tips. Using sanitized pruning shears, remove a cutting from the stems from the garden as desired. Then remove the bottom two to three sets of leaves, allowing 2 to 3 sets to remain.
Fill several small pots equal to your cuttings with potting soil. Dip the cut stems in rooting hormone and press them into the pots. Keep the soil moist, and in a few weeks, you’ll have new growth at the tips of the cut stems.
Troubleshooting Jerusalem Sage
There aren’t many issues to contend with when it comes to these deer-resistant and mostly pest-resistant garden plants. However, there are a few things to look out for. Let’s take a look at those now.
You may have an issue with an overwhelming amount of Phlomis depending on how many plants you have grown. If you’re like me and know you tend to overplant your gardens, take a look at a plant calculator before you begin gardening with this Turkey native.
Monitor those Phlomis species planted in shade. They may get leggy and lack flower petals as the tips extend and search for light. You may experience a ton of spread if you don’t clip back the blooms in autumn. It’s fine to leave the seed for native wildlife to consume in cooler months. Note that you may need to pull up newly planted seeds from each germinated dried flower head in spring if you provide habitat.
This deer-resistant plant also wards off most species of disadvantageous insects as well. The only insect that can be a problem is the leafhopper, which can spread diseases to the leaves and flower stems of your plant as they hop around.
If you search and find them, spray the sage planted in your garden with water. Keep the area around your plant clean, and dust this evergreen with diatomaceous earth or kaolin clay to keep them away. Keep these off and away from the flower heads to avoid harming pollinators.
Diseases of Jerusalem Sage
There are very few to no diseases to worry about when gardening Phlomis evergreen plants. They are incredibly resistant to oak root fungus, which tends to crop up in years when there are heat-filled early summer and moist winter months.
However, overwatered plants can experience root rot in warmer USDA zones in early summer. Make sure your sage garden receives enough water in the hot summer to help your plants flower, but not so much that it stands in water constantly. Similarly, plants in shade may be more susceptible.
The rule of thumb here is to ensure the top 3 to 4 inches of garden soil are dry before watering occurs again. This will keep your sage evergreen and promote the attraction of butterflies and other pollinators to the bright yellow flowers.
Frequently Asked Questions
Q: What is Jerusalem sage used for?
A: The bright yellow flower color provides a splash of color in a flower garden, as well as a pollen source for bees, hummingbirds, and butterflies. You can also use the leaves like culinary sage in cooking.
Q: Is Jerusalem sage invasive?
A: Technically, it’s not, but the plant can be a beast in the garden, spreading out after several summer seasons. Deadhead the flowers to control some of the spread.
Q: Is Jerusalem sage hardy?
A: In most places, yes! Jerusalem sages are perfect for a garden of semi-perennials in zones 5 to 7, and a garden of perennials in zones 8 to 10.
Q: Is Jerusalem sage a salvia?
A: It is not salvia, though it is in the mint family with salvia. One dead giveaway is the structure of the flowers.
Q: Should Jerusalem sage be deadheaded?
A: Yes! Deadhead the flowers in the early part of the season to encourage blooms later in the summer. Then deadhead each flower again in the fall to prevent a spreading mass of Phlomis in your garden.
Q: Can you grow Jerusalem sage from cuttings?
A: You definitely can, and it’s the quickest way to propagate Phlomis fruticosa.
Q: Is phlomis Fruticosa edible?
A: The leaves are edible and can be used much like culinary sage.
Q: Where is phlomis Fruticosa native to?
A: This shrub is native to the Mediterranean.